Potential effects of energy development on environmental resources of the Williston Basin in Montana, North Dakota, and South Dakota—Water resources
<p>The Williston Basin has been a leading oil and gas producing area for more than 50 years. While oil production initially peaked within the Williston Basin…
Public-domain full text preserved in the Mountain Man Mining Library. Original source: pubs.usgs.gov.
Prepared in cooperation with the Bureau of Land Management Potential Effects of Energy Development on Environmental Resources of the Williston Basin in Montana, North Dakota, and South Dakota—Water Resources Chapter C of Potential Effects of Energy Development on Environmental Resources of the Williston Basin in Montana, North Dakota, and South Dakota Scientific Investigations Report 2017-5070-C Version 1.1, October 2022 U.S. Department of the Interior U.S. Geological Survey
Front cover. An oil well pump jack in a grassland in Stark County, North Dakota. Photograph by Larry D. Igl, U.S. Geological Survey. Back cover. An oil well pump jack in a grassland in Fallon County, Montana. Photograph by Larry D. Igl, U.S. Geological Survey.
Potential Effects of Energy Development on Environmental Resources of the Williston Basin in Montana, North Dakota, and South Dakota—Water Resources By Timothy T. Bartos, Steven K. Sando, Todd M. Preston, Gregory C. Delzer, Robert F. Lundgren, Rochelle A. Nustad, Rodney R. Caldwell, Zell E. Peterman, Bruce D. Smith, Kathleen M. Macek-Rowland, David A. Bender, Jill D. Frankforter, and Joel M. Galloway Chapter C of Potential Effects of Energy Development on Environmental Resources of the Williston Basin in Montana, North Dakota, and South Dakota Prepared in cooperation with the Bureau of Land Management Scientific Investigations Report 2017-5070-C Version 1.1, October 2022 U.S. Department of the Interior U.S. Geological Survey
U.S. Geological Survey, Reston, Virginia: 2022 First release: 2022 Revised: October 2022 (ver. 1.1) For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit ://www.usgs.gov or call 1-888-ASK-USGS. For an overview of USGS information products, including maps, imagery, and publications, visit ://store.usgs. gov/. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Bartos, T.T., Sando, S.K., Preston, T.M., Delzer, G.C., Lundgren, R.F., Nustad, R.A., Caldwell, R.R., Peterman, Z.E., Smith, B.D., Macek-Rowland, K.M., Bender, D.A., Frankforter, J.D., and Galloway, J.M., 2022, Potential effects of energy development on environmental resources of the Williston Basin in Montana, North Dakota, and South Dakota— Water resources (ver. 1.1, October 2022): U.S. Geological Survey Scientific Investigations Report 2017-5070-C, 159 p., ://doi.org/10.3133/sir20175070C. Associated data for this report: Boughton, G.K., Sando, S.K., Preston, T.M., Delzer, G.C., Nustad, R.A., Lundgren, R.F., Bender, D.A., and Caldwell, R.R., 2022, Results of water resource data aggregations within areas of energy development in the Williston Basin in Mon tana, North Dakota, and South Dakota: U.S. Geological Survey data release, ://doi.org/10.5066/F77080B9. ISSN 2328-0328 (online)
Acknowledgments This work was prepared in cooperation with the Bureau of Land Management. The authors would like to thank the members of the Bakken Federal Executive Group that partici pated in the initial scoping workshop that resulted in the topical areas covered in this report. We would also like to thank Timothy McHale and Peter McMahon of the U.S. Geological Survey for their comments on this report.
Contents Acknowledgments iii Abstract 1 Introduction 2 Energy Development in the Williston Basin 6 Purpose and Scope 6 Groundwater Resources 7 Most-Used Hydrogeologic Units 7 Glacial Aquifer System 14 Lower Tertiary Aquifer System 14 Upper Cretaceous Aquifer System 14 Groundwater Budget and Flow System 15 Other Hydrogeologic Units 17 Upper Cretaceous Confining Unit 17 Lower Cretaceous Aquifer System 17 Jurassic-Triassic-Permian Confining Unit 18 Paleozoic Aquifers/Aquifer Systems 18 Upper Paleozoic Units 18 Lower Paleozoic Units 21 Groundwater-Flow System 22 River and Stream Resources 26 Available Streamflow Data 26 Streamflow Characteristics 29 Streamflow Data Compilation and Analysis 29 Major Rivers 36 Description of Major River Hydrography 36 Description of Major River Streamflow Characteristics 37 Large Streams 38 Large Streams in the Northern and Northwestern Glaciated Plains Ecoregions 39 Large Streams in Northwestern Great Plains 40 Lake and Wetland Resources 42 Spatial Distribution of Lakes and Wetlands 42 Proximity of Lakes and Wetlands to Energy Development 44 Quality of Water Resources 47 Water-Quality Data Consolidation 48 Development of Water-Quality Dataset 49 Selection of Water-Quality Data for Analyses 50 Groundwater Data 52 River and Streams Data 52 Lakes and Reservoirs Data 52 Characterization of Water Quality in the Williston Basin 52 Groundwater Quality 53 Water Quality of Streams and Rivers 64 Water Quality of Lakes and Reservoirs 76
Produced Water 93 Development of a Produced Water-Quality Dataset 93 U.S. Geological Survey National Produced Waters Geochemical Database 94 U.S. Geological Survey Produced Water Data, 2010 through 2014 94 General Quality of Produced Water 95 Water-Quality Constituents of Concern in Produced Water 97 Characterization of Produced Water 97 Water-Use Data 103 Energy Development and Water Use 105 Coal 105 Thermoelectric Powerplants 105 Oil and Gas 107 Hydropower 108 Biomass and Biofuels 109 Wind 109 Geothermal 110 Solar 110 State Water-Use Regulations and Permitting Legislation 110 North Dakota 111 Montana 111 South Dakota 111 Research and Information Needs 112 Groundwater Resources 112 River and Stream Resources 112 Quality of Water Resources 113 Produced Water 114 Water-Use Data 114 Summary 115 Groundwater Resources 115 River and Stream Resources 116 Lakes and Wetland Resources 116 Quality of Water Resources 117 Produced Water 117 Water-Use Data 118 Research and Information Needs 118 References Cited 118 Appendix C1 133
Figures
1. Map showing geographic extent of the glacial and Northern Great Plains aquifer systems in the United States in relation to the Williston Basin 3
2. Lithostratigraphic units and corresponding hydrogeologic units in the Williston Basin, Glacial and Northern Great Plains aquifer systems, United States and Canada 4
3. Diagrammatic hydrogeologic cross-section A-A' through part of the Northern Great Plains aquifer system 8
4. Map showing geographic extent of the glacial, lower Tertiary, and Upper Cretaceous aquifer systems and corresponding hydrogeologic units within and around the Williston Basin, and the cross-section B-B', United States and Canada 9
5. Generalized cross section showing three-dimensional framework of the glacial, lower Tertiary, and Upper Cretaceous aquifer systems in the Williston Basin 10
6. Hydrogeologic cross-section B-B' showing the glacial, lower Tertiary, and Upper Cretaceous aquifer systems in the Williston Basin 11
7. Map showing thickness of the glacial aquifer system in and near the Williston Basin 12
8. Thickness of the combined lower Tertiary and Upper Cretaceous aquifer systems in the Williston Basin 13
9. Potentiometric surfaces of the upper Fort Union aquifer, lower Fort Union aquifer, and Upper Cretaceous aquifer system in the Williston Basin 16
10. Map showing general areas of recharge to, discharge from, and groundwater flow in the Lower Cretaceous aquifer system in the Williston Basin and adjacent areas, United States and Canada 19
11. Map showing dissolved-solids concentrations in water from the Lower Cretaceous aquifer system in the Williston Basin 20
12. Map showing general areas of recharge to the Paleozoic aquifers/aquifer systems, and general direction of groundwater flow in, and discharge from, the Pennsylvanian aquifer system in the Williston Basin and adjacent areas, United States and Canada 23
13. Map showing general areas of recharge to the Paleozoic aquifers/aquifer systems, and general direction of groundwater flow in, and discharge from, the Madison aquifer in the Williston Basin and adjacent areas, United States and Canada 24
14. Map showing general areas of recharge to the Paleozoic aquifers/aquifer systems, and general direction of groundwater flow in, and discharge from, the Cambrian-Ordovician aquifer system in the Williston Basin and adjacent areas, United States and Canada 25
15. Map showing dissolved-solids concentrations in water from upper Paleozoic aquifers in the Williston Basin and adjacent areas 27
16. Map showing dissolved-solids concentrations in water from the lower Paleozoic aquifers and confining units in the Williston Basin and adjacent areas 28
17. Map showing locations of selected streamgages on major rivers and large streams in or near the Williston Basin 32
18. Graphs showing duration hydrograph streamflow statistics and annual extreme flows for selected streamgages on major rivers in the Williston Basin, Montana, North Dakota, and South Dakota 33
19. Graphs showing duration hydrograph streamflows and annual extreme flows for selected streamgages on large streams in the Northern and Northwestern Glaciated Plains ecoregions 34
20. Graphs showing duration hydrograph streamflows and annual extreme flows for selected streamgages on large streams in the Northwestern Great Plains ecoregion 35
21. Map showing proximity of surface-water features to oil and gas wells in the Williston Basin 43
22. Summary statistics of surface-water features, not including streams and rivers, for the top 25 counties in the Williston Basin, ranked by total number of surfacewater features, total area of surface-water features, and the percentage of the County covered by surface-water features 45
23. The top 25 counties wholly or partially in the Williston Basin, ranked by total number, area, and percentage of surface-water features within 0.4 kilometer of at least one oil or gas well 48
24. The top 25 counties wholly or partially in the Williston Basin, ranked by total number, area, and percentage of surface-water features within 0.8 kilometer of at least one oil or gas well 49
25. The top 25 counties wholly or partially in the Williston Basin, ranked by total number, area, and percentage of surface-water features within 1.6 kilometers of at least one oil or gas well 50
26. Number of stream and river samples collected in the Williston Basin, 1970 through 2015 51
27. Graphs showing range and statistical distribution of specific conductance, total dissolved-solids concentrations, pH, sulfate concentrations, and chloride concentrations measured in groundwater samples from the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 58
28. Map showing specific conductance and median specific conductance measured in groundwater samples from wells in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 59
29. Map showing total dissolved-solids concentrations and median total dissolvedsolids concentrations measured in groundwater samples from wells in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 60
30. Map showing pH and median pH measured in groundwater samples from wells in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 through 2014 61
31. Map showing sulfate concentrations and median sulfate concentrations measured in groundwater samples from wells in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 through 2014 62
32. Map showing chloride concentrations and median chloride concentrations measured in groundwater samples from wells in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 through 2014 63
33. Map showing spatial distribution of specific conductance samples from streams and rivers and numbers of oil and gas wells in HUC-8 watersheds in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 66
34. Map showing specific conductance in streams and rivers in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 67
35. Graphs showing annual variability in values of constituents for all streams and rivers in the Williston Basin, from 1970 to 2014 68
36. Graphs showing annual variability in values of constituents for the Yellowstone River near Sidney, Montana, from 1970 to 2014 71
37. Maps showing total dissolved-solids concentrations in streams and rivers in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 74
38. Maps showing pH in streams and rivers in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 75
39. Maps showing sulfate concentrations in streams and rivers in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 77
40. Maps showing chloride concentrations in streams and rivers in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 78
41. Map showing spatial distribution of specific conductance samples from lakes and reservoirs and numbers of oil and gas wells in hydrologic unit code-8 watersheds in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 79
42. Map showing location of select water-quality sites on Lake Sakakawea sampled from 1993 to 2014 80
43. Maps showing specific conductance in lakes in Montana, North Dakota, and South Dakota, from 1970 to 2014 82
44. Graphs showing annual variability in values of constituents in all lakes across the Willison Basin by year from 1970 to 2014 83
45. Graphs showing annual variability in values of constituents in Lake Sakakawea by year from 1993 to 2014 86
46. Graph showing annual mean water surface elevation in Lake Sakakawea from 1993 to 2014 87
47. Graphs showing range and statistical distribution of specific conductance, total dissolved solids, pH, sulfate, and chloride measured at sites in Lake Sakakawea from 1993 to 2014 88
48. Maps showing total dissolved-solids concentrations in lakes in the Williston Basin in Montana, North Dakota, and South Dakota, 1970 to 2014 89
49. Maps showing values of pH in lakes in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014 90
50. Maps showing sulfate concentrations in lakes in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 through 2014 91
51. Maps showing chloride concentrations in lakes for Montana, North Dakota, and South Dakota, from 1970 through 2014 92
52. Photograph showing oil and produced water collected from an unconventional Bakken Formation production well near Sidney, Montana, August 2014 93
53. Map showing location of 30 oil-production well sites within the Williston Basin for which the U.S. Geological Survey analyzed samples, 2010 through 2014 95
54. Graph showing the distribution of total dissolved solids in produced waters from geologic formations in the United States 97
55. Maps showing spatial distribution of total dissolved-solids concentrations, in milligrams per liter, for samples included in the U.S. Geological Survey National Produced Waters Geochemical Database in Montana, North Dakota, and South Dakota 98
56. Graphs showing range and statistical distribution of concentrations of calcium, sodium, chloride, and total dissolved solids in produced-water samples from the Williston Basin, Montana, North Dakota, and South Dakota, including all samples in the U.S. Geological Survey National Produced Waters Geochemical Database as well as from the Madison Group, Bakken Formation, and Red River Formation 99
57. Graph showing total dissolved solids in milligrams per liter relative to depth of mineshaft seeps of the northern Williston Basin, Saskatchewan, Canada 102
58. Graph showing oxygen and hydrogen isotopic composition of modern seawater, produced-water samples from the Bakken, Birdbear, and Duperow Formations, and mineshaft water samples 102
59. Graph showing comparison of strontium concentrations and isotope ratios of produced water in the Poplar Dome of eastern Montana and the Bakken Formation of eastern Montana and North Dakota 103
60. Map showing coal-fired powerplants and water withdrawals in million gallons per year by cooling technology, in the United States, 2008 106
61. Dams of the Missouri River main-stem system in downstream order according to river miles and the storage capacity of each dam and reservoir complex 108 Tables
1. Interpolated volumes, thicknesses, and horizontal hydraulic conductivity values of the glacial, lower Tertiary, and Upper Cretaceous aquifer systems in the Williston Basin 6
2. Estimated average groundwater recharge and discharge components for 1981 through 2005 for the combined glacial, lower Tertiary, and Upper Cretaceous aquifer systems within the Williston Basin control volume area 15
3. Information on selected streamgages on major rivers and large streams in or near the Williston Basin, 1954 through 2014 30
4. The total number, area, and percentage of coverage of surface-water features, not including streams and rivers, for the Williston Basin and the parts of the Williston Basin inside and outside of the Prairie Pothole Region 44
5. The total number, area, and percentage of coverage of surface-water features, not including streams and rivers, for the parts of Montana, North Dakota, and South Dakota within the Williston Basin 44
6. Total number, area, and percentage of surface-water features, not including streams and rivers, near oil and gas wells in the Williston Basin and the parts of the Williston Basin inside and outside of the Prairie Pothole Region 46
7. Total number, area, and percentage of surface-water features, not including streams and rivers, near oil and gas wells in the parts of Montana, North Dakota, and South Dakota in the Williston Basin 47
8. Summary of trace metals measured in groundwater samples from the Williston Basin, from 1993 to 2014 54
9. Summary of selected trace metal data in the Williston Basin at stream and river sites that had 10 or more samples collected during 1993 through 2014 56
10. Summary of selected trace metal data in the Williston Basin at lake sites with samples analyzed during 1993 through 2014 57
11. Constituent list for characterization of produced waters in the Williston Basin, 2010 through 2014 96
12. Generalized water chemistry of produced waters collected within the Williston Basin, including samples collected from the Bakken Formation, the Madison Group, and Red River Formation; groundwater samples collected from water-supply wells in the upper Fort Union Formation in Montana and North Dakota; and typical seawater 96
13. Generalized water chemistry of produced-water samples collected from the Bakken and Three Forks Formations, Williston Basin, Montana and North Dakota as part of U.S. Geological Survey study efforts 2010 through 2014 and Bakken Formation samples included in the U.S. Geological Survey Produced Waters Geochemical Database v2.1 100
14. Summary of concentrations of selected chemical constituents in producedwater samples stored in the U.S. Geological Survey Produced Waters Geochemical Database v2.1 for sites within the Williston Basin, Montana, North Dakota, and South Dakota 100
15. Summary of selected physical properties and chemical constituents collected within the Williston Basin area of Montana and North Dakota, and analyzed by U.S. Geological Survey, 2010 through 2014 101
16. List of energy resources developed in the Williston Basin with U.S. energy consumption for 2011 and 2014, and water-use requirements for each energy resource 104
17. Water use for thermoelectric power cooling by type for conventional coal-fired powerplants in the Williston Basin, in gallons per megawatthour 106
18. Total self-supplied water withdrawals and power generated by thermoelectric powerplants for selected counties in North Dakota and Montana for 2005 and 2010 107
19. Active drilling rig counts for North Dakota, Montana, and South Dakota based on average count for January, 2005 to 2015 107
20. National water-use summary estimates for biofuels production 109
Conversion Factors U.S. customary units to International System of Units Multiply By To obtain Length inch (in.) centimeter (cm) inch (in.) millimeter (mm) foot (ft) meter (m) mile (mi) kilometer (km) yard (yd) meter (m) Area acre 4,047 square meter (m2) acre hectare (ha) acre square hectometer (hm2) acre square kilometer (km2) square foot (ft2) square centimeter (cm2) square foot (ft2) square meter (m2) square mile (mi2) hectare (ha) square mile (mi2) square kilometer (km2) Volume barrel (bbl; petroleum, 1 barrel=42 gal) cubic meter (m3) gallon (gal) liter (L) gallon (gal) cubic meter (m3) gallon (gal) cubic decimeter (dm3) million gallons (Mgal) 3,785 cubic meter (m3) billion gallons (Bgal) 3,785,412 cubic meter (m3) cubic inch (in3) cubic centimeter (cm3) cubic foot (ft3) cubic decimeter (dm3) cubic foot (ft3) cubic meter (m3) acre-foot (acre-ft) 1,233 cubic meter (m3) acre-foot (acre-ft) cubic hectometer (hm3) million acre-feet (MAF) 1.2335×109 cubic meter (m3)
Multiply By To obtain Flow rate acre-foot per year (acre-ft/yr) 1,233 cubic meter per year (m3/yr) acre-foot per year (acre-ft/yr) cubic hectometer per year (hm3/yr) foot per day (ft/d) meter per day (m/d) foot per year (ft/yr) meter per year (m/yr) cubic foot per second (ft3/s) cubic meter per second (m3/s) cubic foot per day (ft3/d) cubic meter per day (m3/d) gallon per minute (gal/min) liter per second (L/s) million gallons per day (Mgal/d) cubic meter per second (m3/s) inch per year (in/yr) millimeter per year (mm/yr) Mass pound, avoirdupois (lb) kilogram (kg) ton, short (2,000 lb) megagram (Mg) Energy kilowatthour (kWh) 3,600,000 joule (J) megawatthour (MWh) 3.6×109 joule (J) gigawatthour (GWh) 3.6×1012 joule (J) Radioactivity picocurie per liter (pCi/L) becquerel per liter (Bq/L) Hydraulic conductivity foot per day (ft/d) meter per day (m/d) Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as
°F (1.8 × °C) + 32. Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as
°C (°F - 32) / 1.8. Datum Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88). Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).
Supplemental Information Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (µS/cm at 25 °C). Concentrations of chemical constituents in water are given in either milligrams per liter (mg/L) or micrograms per liter (µg/L). Activities for radioactive constituents in water are given in picocuries per liter (pCi/L). A water year is the period from October 1 to September 30 and is designated by the year in which it ends; for example, water year 2015 was from October 1, 2014, to September 30, 2015. Stable isotope ratios of oxygen (18O/16O) and hydrogen (2H [deuterium]/1H) are shown in delta (δ) notation as δ18O and δ2H, in per mil (parts per thousand). Abbreviations AL action level BFEG Bakken Federal Executive Group CGCSRL Geophysics and Geochemistry Science Center Laboratory CO2 carbon dioxide δ2H a measure of the ratio of stable isotopes hydrogen-2 and hydrogen-1 δ18O a measure of the ratio of stable isotopes oxygen-18 and oxygen-16 EIA U.S. Energy Information Administration EPA U.S. Environmental Protection Agency EPRI Electric Power Research Institute GIS geographic information system HUC Hydrologic Unit Code MBMG Montana Bureau of Mines and Geology MCL maximum contaminant level MDEQ Montana Department of Environmental Quality NAWQA National Water-Quality Assessment NDDH North Dakota Department of Health NDSWC North Dakota State Water Commission NHD National Hydrography Dataset NHDPlus National Hydrography Dataset Plus Version 2 NPWGD National Produced Waters Geochemical Database
NWI National Wetlands Inventory NWIS National Water Information System NWQL National Water Quality Laboratory NWQMC National Water-Quality Monitoring Council PRISM Parameter-elevation Regression on Independent Slopes Model PV photovoltaics Reclamation Bureau of Reclamation RM river mile SDDENR South Dakota Department of Environment and Natural Resources SMCL secondary maximum contaminant level SNG synthetic natural gas STEWARDS Sustaining the Earth's Watersheds-Agricultural Research Database System STORET Storage and Retrieval data warehouse SWSTAT U.S. Geological Survey Surface-Water Statistics program TDS total dissolved solids USACE U.S. Army Corp of Engineers USDA U.S. Department of Agriculture USFWS U.S. Fish and Wildlife Service USGS U.S. Geological Survey WQP Water-Quality Portal
Potential Effects of Energy Development on Environmental Resources of the Williston Basin in Montana, North Dakota, and South Dakota—Water Resources By Timothy T. Bartos, Steven K. Sando, Todd M. Preston, Gregory C. Delzer, Robert F. Lundgren, Rochelle A. Nustad, Rodney R. Caldwell, Zell E. Peterman, Bruce D. Smith, Kathleen M. Macek-Rowland, David A. Bender, Jill D. Frankforter, and Joel M. Galloway Abstract The Williston Basin has been a leading oil and gas producing area for more than 50 years. While oil production initially peaked within the Williston Basin in the mid-1980s, production rapidly increased in the mid-2000s, largely because of improved horizontal (directional) drilling and hydraulic fracturing methods. In 2012, energy development associ ated with the Bakken Formation was identified as a priority requiring collaboration toward improved timeliness of issuing permits for new wells combined with reasonable measures to maintain environmental quality. Shortly thereafter, the Bak ken Federal Executive Group was created to address common challenges associated with energy development. The Bakken Federal Executive Group partner agencies identified a gap in current understanding of the cumulative environmental chal lenges attributed to energy development throughout the area, resulting in an effort to aggregate scientific data and identify additional research and information needs related to natural resources within areas of energy development in the Williston Basin. As part of this effort, water resources in the area (includ ing groundwater; streams and rivers; and lakes, reservoirs, and wetlands) were characterized and described in terms of physical occurrence, flow characteristics, recharge, water qual ity, and water use. Similarly, waters produced during energydevelopment activities also were characterized even though these waters are not considered usable resources within the area. Groundwater resources were characterized by the major hydrogeologic units, or aquifers, identifying the units that sup ply most groundwater used for domestic, stock, agricultural, and industrial purposes. The groundwater characterization included other deeper hydrogeologic units in the Williston Basin that may be a useable source of water with treatment, have utility as a reservoir for reinjection of produced waters, or be a source of minerals and energy resources. A generalized groundwater budget and flow system identifying the sources of recharge (stream infiltration, precipitation, and movement [leakage] from other aquifers) and the general groundwater flow direction is included for each of the major hydrogeologic units. Rivers and streams within the Williston Basin with 10 or more years of continuous streamflow data were identi fied. For a subset of these sites, streamflow characteristics, including the monthly and annual mean flow, were generated to identify seasonal and interannual changes in streamflow and thus provide information on the drivers and reliability of streamflow at the seasonal or multiyear scale. Daily stream flow and annual extreme flows (peak and low flow) also were estimated for the subset of sites. The daily streamflow and annual extreme flow values provide information on short-term or extreme events that are relevant to infrastructure design and evaluating spills, leaks, or accidental discharges of water or petroleum products. Surface-water features (lakes, ponds, and wetlands) were classified using the Cowardin system and identified on the National Wetlands Inventory maps generated by the U.S. Fish and Wildlife Service. The spatial distribution of the surface-water features was analyzed by State, county, and specifically in comparison to the Prairie Pothole Region. The proximity of the surface-water features to energy devel opment infrastructure (specifically oil or gas well pads) was evaluated. It was determined that, although oil or gas wells are often near a surface-water feature, most surface-water features do not have wells nearby, with the exception of wells in the Prairie Pothole Region. Water-quality data were aggregated from two data sources: (1) the Water-Quality Portal, sponsored by the U.S. Geological Survey (USGS), U.S. Environmental Protection Agency (EPA), and National Water Quality Moni toring Council; and (2) a data compilation completed as part of the USGS National Water-Quality Assessment project. The Water-Quality Portal integrates publicly available waterquality data from databases maintained by the USGS, EPA, and U.S. Department of Agriculture, including water-quality data from Tribal, State, and local databases. Water-quality data for 15 commonly measured water-quality constituents were aggre gated for groundwater, rivers and streams, and lakes and res ervoirs. For each aggregated dataset (groundwater, rivers and streams, and lakes and reservoirs), analyses of the water-quality data included summary statistics, maps of spatial distribution of constituent values, boxplots of constituent values by timeframe or hydrogeologic unit, spatial comparisons of site locations and constituent values to petroleum well density, and comparisons
2 Potential Effects of Energy Development, Williston Basin—Water Resources of the constituent values measured to EPA drinking-water stan dards/guidelines. Produced water includes all fluids brought to the surface along with the targeted hydrocarbons as part of the oil and gas exploration and extraction processes. These fluids may include formation water (waters that co-exist with rock/ oil/gas), hydraulic fracturing fluids, and other combinations of water and chemicals used during oil and gas well drill ing, development, treatments, recompletions, and workovers. Produced water datasets were aggregated from two sources: the USGS National Produced Waters Geochemical database (ver. 2.1) and a series of projects focused specifically on sampling produced water in the Williston Basin from 2010 to 2014. The National Produced Waters Geochemical database was use ful for a general understanding of produced-water chemistry. Produced waters are characterized by extreme salinity and contain elevated concentrations of other constituents (including arsenic, barium, cadmium, lead, zinc, radium-226/radium-228, and ammonium) that could negatively affect water and aquatic resources if released. Produced waters also have a generally unique chemical (isotopic) signature that may be useful in tracking water from different geologic units; for example, the oxygen/deuterium and strontium ratio values measured in brine waters from the Bakken Formation are distinct from brines col lected from other geologic units in the Williston Basin. Water-use information related to energy production in the area also was aggregated and summarized. The summary of water use is not limited to oil and gas production but includes water used to produce all types of energy resources in the Wil liston Basin, including coal/lignite, thermoelectric power, oil and gas, hydropower, biomass and biofuels, wind, geothermal, and solar. Each State has its own methods for regulating and reporting water usage within its jurisdiction. These methods can introduce problems when examining water use from sources, such as the Missouri River or Fox Hills aquifer, that are shared across political boundaries. Without the one-to-one match for usage types and amounts used from a water source, it is difficult to develop a comprehensive water budget for the water source being evaluated. A large amount of freshwater is required to prepare a well for oil and gas well production; in some cases, 3 to 7 million gallons of water are needed per well. The EPA estimates that hydraulic fracturing in the Williston Basin uses between 70 to 140 billion gallons per year. Water also is used for myriad other purposes related to ancillary oil and gas extraction. In addition to water used for immediate energy development, the expanded human workforce migrating into the area and other support staff who have moved into the area during the development also use water. Research and information needs were identified that could be relevant in the evaluation of the effects of energy development on water resources. Information needs related to the evaluation of groundwater resources include the follow ing: improved potentiometric-surface maps for glacial units; availability of a uniform stream network digital geographic coverage that spans the international boundary with Canada; enhanced surface-water use information with regards to the gain and loss of streamflow to shallow groundwater, which would increase understanding groundwater and surface-water interactions; and expanded geophysical assessments. Gaps in the availability of streamflow data include the lack of informa tion on ice-jam flooding despite potential for effects to infra structure (pipelines, roads, and facilities) and an understanding of the cumulative effects of largely undocumented stock and diversion dams. Although this study resulted in the aggregation of a large quantity of water-quality data, the availability of con sistently collected, systematically processed and reported data over large parts of the Williston Basin is sparse. Few samples have been analyzed for constituents that may indicate the effect of energy development on water resources. Constituents that could be considered include boron, chloride, bromide, iodine, fluoride, manganese, lithium, radium, strontium isotopes, vola tile organic compounds, and isotopes of inorganic ions (such as hydrogen and carbon). Collaboration between Tribal, Federal, State, and local entities to identify a common study design, common monitoring constituents, and consistent sampling locations would generate datasets with broad utility and would likely result in overall cost savings for monitoring over time. Similarly, there is a need for standardized sample collection, processing, laboratory analytical methods, and the collection of ancillary data for produced waters sampling. Additional characterization of the range of chemical, microbial, and iso topic compositions and quantities of "end-member" produced waters, and the collection of time-series datasets to document the changes in produced waters during and after well develop ment also were needs identified during this study. Water-use estimates would be improved through the implementation of comprehensive studies of water use from groundwater and surface-water sources using consistent methodologies across the Williston Basin. The submission of chemical and water data related to hydraulic fracturing collected by the oil and gas industry would add to the quantity of available data. Consistent implementation of regulations and monitoring controls across political boundaries (State, county, and international) would further improve the consistency of data available for the esti mates of water use. Introduction The Williston Basin energy development area (hereinafter referred to as the "Williston Basin"), includes parts of Mon tana, North Dakota, and South Dakota in the United States and the provinces of Manitoba and Saskatchewan in Canada (fig. 1), and has been a leading energy production area since the 1950s (Anna and others, 2011; Gleason and Tangen, 2014; Thamke and others, 2014). Because demands for energy con tinued to increase, energy development in the Williston Basin increased substantially beginning in the mid-2000s, primarily because of improved horizontal drilling and hydraulic fractur ing methods used in previously inaccessible formations, such as the Bakken and Three Forks Formations (fig. 2) (Gaswirth and others, 2013).
Introduction 3 Map area Map area CANADA CANADA UNITED STATES UNITED STATES MEXICO MEXICO 300 MILES 300 KILOMETERS 95° 100° 105° 110° 50° 45° Fargo Casper Pierre Helena Cheyenne Billings Bismarck Rapid City Sioux Falls Grand Forks Great Falls MANITOBA SASKATCHEWAN ONTARIO ALBERTA MINNESOTA NORTH DAKOTA MONTANA IDAHO WYOMING NEBRASKA COLORADO UTAH IOWA Cedar Lake LAKE MANITOBA Lake Winnipegosis Fort Peck Lake Lake Sakakawea Lake Oahe M isso u ri
R e r
Yellowstone Lake SOUTH DAKOTA
M is so ur R ive r Upper Cretaceous aquifer system Lower Cretaceous aquifer system Lower Tertiary aquifer system Northern Great Plains aquifer system boundary (Whitehead, 1996)— Dashed where approximate Williston Basin boundary (Gleason and Tangen, 2014) Bakken Formation boundary (Gleason and Tangen, 2014) Cross section A -A( ׳fig. 3) Not a principal aquifer Paleozoic aquifers Confining unit Northern Great Plains aquifer system hydrogeologic units outcrops or subcrops (Whitehead, 1996) Glacial aquifer system (Thamke and others, 2014) CANADA UNITED STATES EXPLANATION Base from U.S. Geological Survey digital data, variously dated, various scales Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 Lake Sharpe Lake Francis Case Y e o w s t o ne Riv er LAKE WINNIPEG POWDER RIVER BASIN WILLISTON BASIN BULL MOUNTAIN BASIN B A K HI S U P FT Red River of the Nor th A′ A′ A BIGHORN BASIN Figure 1. Geographic extent of the glacial and Northern Great Plains aquifer systems in the United States in relation to the Williston Basin.
4 Potential Effects of Energy Development, Williston Basin—Water Resources Sentinel Butte Member5 Lower Fort Union aquifer Middle Fort Union hydrogeologic unit Upper Fort Union aquifer CENOZOIC MESOZOIC Cretaceous Quaternary Jurassic Pliocene4 Tertiary 4 Upper Lower Dakota Group11 Miocene4 Eocene Oligocene4 Paleocene PALEOZOIC (part) Triassic Permian (part) Fox Hills Sandstone Fox Hills aquifer Newcastle Formation/Sandstone (Dakota Skull Creek Shale11 Swift Formation Rierdon Formation Piper Formation Nesson Formation Fall River Formation/ Sandstone11 Lakota Formation11 Pierre Shale Upper Cretaceous confining unit Carlile Shale Greenhorn Formation Belle Fourche Shale Niobrara Formation Hell Creek Formation8 Mowry Shale10, 11 Morrison Formation Inyan Kara Group11 Inyan Kara Formation11 Inyan Kara aquifer Jurassic-Triassic-Permian confining unit12 Fort Union Formation Upper Hell Creek hydrogeologic unit Lower Hell Creek aquifer Lower Tertiary aquifer system8 Glacial deposits3 Glacial aquifer system3 Minnekahta Limestone Spearfish Formation Opeche Formation Erathem System, series, and other divisions Lithostratigraphic unit1 Hydrogeologic unit2 Golden Valley Formation5 Upper Cretaceous aquifer system9 Skull Creek confining unit Dakota or Newcastle aquifers Dakota aquifer/ aquifer system Lower Cretaceous aquifer system Lebo Shale Member (Slope Fm.)6 Tullock, Ludlow, and Cannonball Members7 Tongue River Member (Bullion Creek Fm.) Northern Great Plains aquifer system (part) Rocks absent due to erosion or nondeposition Unconformity Formation Limestone Fm. Ls. EXPLANATION Figure 2. Lithostratigraphic units and corresponding hydrogeologic units in the Williston Basin, Glacial and Northern Great Plains aquifer systems, United States and Canada.
Bakken-Three Forks confining unit Pennsylvanian Cambrian PALEOZOIC (part) Three Forks Formation Birdbear (Nisku) Formation Duperow Formation Upper Paleozoic aquifers Minnelusa Group or Formation and equivalents13 Pennsylvanian aquifer system Erathem System, series, and other divisions Lithostratigraphic unit1 Hydrogeologic unit2 Madison Group Madison aquifer14 Confining unit Confining unit Big Snowy Group Bakken Formation Confining unit Charles Formation Mission Canyon Limestone Lodgepole Limestone Souris River Formation Dawson Bay Formation Prairie Formation Winnipegosis Formation Interlake Formation Birdbear aquifer Duperow aquifer Souris River-Dawson Bay aquifer15 Cambrian-Ordovician aquifer17 Confining unit Confining unit Winnipegosis aquifer Confining unit Stonewall Formation Stony Mountain Formation Winnipeg Formation Deadwood Formation Red River (Yeoman) Formation Red River aquifer Ashern Formation Confining unit Ordovician Silurian Devonian Mississippian PRECAMBRIAN Interlake-Stonewall aquifer16 Lower boundary of the Northern Great Plains aquifer system 1Compiled from Bluemle (1983, 1988); Bluemle and others (1986); Vuke and others (2007); and Murphy and others (2009). 2Compiled or modified from Downey (1982, 1984a, b, 1986); Bredehoeft and others (1983); Butler, 1984; Case, 1984; Downey and Dinwiddie (1988); Busby and others (1991); Bachu and Hitchon (1996); Whitehead (1996); Benn and Rostron (1998); Alkalali (2002); Margitai (2002); Whittaker and others (2004); Palombi (2008); and Thamke and others (2014). 3Generally located north of the Missouri River. 4Upper Tertiary units (Pliocene, Miocene, and Oligocene) exist only in a small part of the study area and are not included herein. 5Golden Valley Formation present in local areas. Sentinel Butte Member present in central part of the Williston Basin and a small contiguous area in Montana. 6Pinches out north of the Missouri River. Mapped as the Tongue River Formation in South Dakota by Martin and others (2004). 7Cannonball Member present in the southern and eastern parts of the Williston Basin. Slope Formation is above the Cannonball Member in southern North Dakota. Ludlow Member is present in the southern part of North Dakota. 8Includes all but the lower part of the Ravenscrag Formation in Saskatchewan and the Turtle Mountain Formation in Manitoba (Thamke and others, 2014). 9Includes the lower Ravenscrag Formation (Paleocene), the Frenchman and Eastend Formations (Cretaceous) in Saskatchewan, and the Boissevain and Pierre Formations (Cretaceous) in Manitoba (Thamke and others, 2014). 10Mowry Shale is Lower Cretaceous but is inincluded in the Upper Cretaceous confining unit. 11Inyan Kara identified as a formation in North Dakota (Murphy and others, 2009) and as a group consisting of the Fall River Sandstone and Lakota Formation in South Dakota (Fahrenbach, 2010). In North Dakota, the Inyan Kara Formation is grouped with the overlying Skull Creek Shale, Newcastle Formation, and Mowry Shale into the Dakota Group (Murphy and others, 2009). In the Montana portion of the Williston Basin, Inyan Kara generally is not currently (2020) used to identify equivalent strata; however, the Fall River Formation is currently used/recognized and strata equivalent to the Lakota Formation/Sandstone are identified as the Kootenai Formation (Vuke and others, 2007; Condon, 2000). 12Parts of the various lithostratigraphic units composing the Jurassic-Triassic-Permian confining unit are sufficiently permeable in some areas to contain local aquifers. 13Includes the Broom Creek, Tyler, and Amsden Formations where present (Bluemle and others, 1986). 14Also known as the Mississippian aquifer system (Downey and Dinwiddie, 1988; Bachu and Hitchon, 1996). 15Also known as the Manitoba aquifer (Whittaker and others, 2004). 16Also known as the Silurian-Upper Ordovician aquifer (Benn and Rostron, 1998) or the Ordo- Silurian aquifer (Whittaker and others, 2004). 17Also known as the Cambro-Winnipeg aquifer (Benn and Rostron, 1998) or the Cambro-Ordovician aquifer (Whittaker and others, 2004). Northern Great Plains aquifer system (part) Cambrian-Ordovician aquifer system Lower Paleozoic aquifers and confining units Permian (part) Introduction 5 Figure 2. Lithostratigraphic units and corresponding hydrogeologic units in the Williston Basin, Glacial and Northern Great Plains aquifer systems, United States and Canada.— Continued
6 Potential Effects of Energy Development, Williston Basin—Water Resources Executive Order 13604 (March 22, 2012) directs Federal agencies to improve the timeliness of issuing permits for new energy development with the Bakken Formation combined with reasonable measures to maintain environmental quality. Shortly thereafter, the BFEG (see chapter B of this report, table 1) was created to address common challenges associ ated with energy development, with a focus on understanding the cumulative environmental challenges attributed to energy development throughout the area. To improve understand ing of the natural resources in the area, the U.S. Geological Survey (USGS), in cooperation with the Bureau of Land Management, began work to synthesize existing information on environmental resources in the area to support management decisions related to energy development. Energy Development in the Williston Basin Oil exploration began in the Williston Basin (fig. 1) a century ago in 1917, and large-scale production began in the 1950s with nearly continuous exploration since then (Ling and others, 2014). The early stages of production in the Williston Basin began with conventional oil and gas development using vertical wells that extracted hydrocarbons from structural or stratigraphic settings in which the hydrocarbons were trapped within a well-defined water-hydrocarbon interface (Schenk and Pollastro, 2002). Oil production using conventional extraction methods peaked within the Williston Basin in the mid-1980s. Domestic production of both natural gas and oil has increased steadily since 2005 due to increased productivity from unconventional sources (Healy and others, 2015). Unconventional oil and gas resources, such as the Bakken Formation in the Williston Basin, include low-permeability sandstones and shales, often referred to as "tight-oil" formations, and consist of oil and gas dispersed through one or more geologic layers with no obvi ous water-hydrocarbon contact (Healy and others, 2015). The two most important of technological advances that have enabled development of unconventional oil and gas resources within the Williston Basin and elsewhere are (1) horizontal (directional) drilling and (2) hydraulic fractur ing (Healy and others, 2015). Horizontal (directional) drill ing allows wells to extend several thousand feet horizontally within an oil or gas reservoir. Hydraulic fracturing enhances the permeability of the reservoir rock by applying high pres sure using fluid mixtures to isolated sections of the well bore to create fractures in the rock. These hydraulic fracturing flu ids open or enlarge fractures that can extend several hundred feet away from the well. The Williston Basin experienced a large energy boom because of large-scale development of the underlying Bakken Formation. Estimated mean undiscovered volumes of 7.4 bil lion barrels (bbl) of oil, 6.7 trillion cubic feet (ft3) of natural gas, and 0.53 bbl of natural gas liquids in the Bakken and Three Forks Formations (fig. 2) in the Williston Basin indicate energy development will continue in this area (Gaswirth and others, 2013). Purpose and Scope The purpose of this report is to describe the water resources in the Williston Basin in Montana, North Dakota, and South Dakota (fig. 1). Water resources are characterized in terms of the groundwater; streams and rivers; and lakes, reservoirs, and wetlands of the area. The resources also are described in terms of physical occurrence, flow characteris tics, recharge, water quality, and water use. Waters produced during energy development activities also are discussed even though these waters are not considered usable resources in the area. The resources also are described in terms of research and information needs. This report provides information and data that can be used to develop effective techniques to assess issues related to energy development activities. Table 1. Interpolated volumes, thicknesses, and horizontal hydraulic conductivity values of the glacial, lower Tertiary, and Upper Cretaceous aquifer systems in the Williston Basin (modified from Thamke and others, 2014). [Kh, horizontal hydraulic conductivity; --, not available] Hydrogeologic unit or aquifer system Volume, in trillion cubic feet Thickness, in feet Kh, in feet per day Glacial aquifer system 0-756 0.01-24 Lower Tertiary aquifer system 1,002 0-2,246 Upper Fort Union aquifer 0-1,917 0.14-9.8 Middle Fort Union hydrologic unit 0-520 0.01-7.8 Lower Fort Union aquifer 0-668 0.14-5.5 Upper Cretaceous aquifer system 1,005 0-1,047 Upper Hell Creek hydrologic unit 0-738 0.10-5.5 Lower Hell Creek aquifer 0-548 0.10-1.7 Fox Hills aquifer 0-422 0.06-1.0
Groundwater Resources 7 Groundwater Resources Groundwater in the Williston Basin (fig. 1) is pres ent in aquifers composed of water-saturated and permeable unconsolidated glacial and alluvial deposits of Quaternary age, and water-saturated and permeable consolidated sedi mentary bedrock ranging from Tertiary to Cambrian in age (fig. 2). Aquifers in the Tertiary- to Cambrian-age sedimentary bedrock and all intervening impermeable or low-permeability layers (confining units) in the Williston Basin are part of a thick, areally extensive regional transboundary aquifer system in the United States and Canada identified as the Northern Great Plains aquifer system (figs. 1 and 2) (Downey, 1984a, 1984b, 1986, 1987; Dinwiddie and Downey, 1986; Downey and others, 1987; Downey and Dinwiddie, 1988; Whitehead, 1996). In the United States, this aquifer system covers not only the Williston Basin in North and South Dakota and Montana, but also parts of Wyoming and a small area in northwestern Nebraska (fig. 1). As shown in cross section A-A′, numerous permeable and intervening low-permeability lithostratigraphic units or parts of units compose the hydrogeologic units (aquifers/aquifer systems and confining units) of the regional Northern Great Plains aquifer system (figs. 1-3). Sedimentary bedrock aqui fers consist primarily of Tertiary- and Cretaceous-age sand stones and Paleozoic-age carbonate rocks and less commonly of sandstones (Downey, 1984a, 1984b, 1986, 1987; Brede hoeft and others, 1983; Butler, 1984; Downey and others, 1987; Hannon, 1987; Downey and Dinwiddie, 1988; Busby and others, 1995; Bachu and Hitchon, 1996; Whitehead, 1996; Benn and Rostron, 1998; LeFever, 1998; Thamke and others, 2014). Precambrian-age igneous rocks that underlie the North ern Great Plains aquifer system (fig. 3) in the Williston Basin are deeply buried, yield little water, and are considered to be the lower boundary of the aquifer system (Downey, 1986; Downey and Dinwiddie, 1988; Bachu and Hitchon, 1996; Benn and Rostron, 1998). Widely distributed unconsolidated glacial and locally present alluvial deposits overlie parts of the Northern Great Plains aquifer system throughout much of the Williston Basin. Water-saturated and permeable parts of these deposits are extensively developed (for example, Paulson, 1983; Winter and others, 1984) and are the sources of water to thousands of wells in the Williston Basin. Because shallow groundwater flow in these deposits is primarily local and substantially dif ferent from the predominantly deep confined regional flow in the underlying bedrock aquifers, glacial and alluvial aquifers generally are not included as part of the Northern Great Plains aquifer system (Downey, 1986; Downey and Dinwiddie, 1988; Whitehead, 1996). Three uppermost principal aquifer systems supply most groundwater used in the Williston Basin. From shallowest (stratigraphically youngest) to deepest (stratigraphically old est), these are the glacial, lower Tertiary, and Upper Creta ceous aquifer systems (fig. 2). The lower Tertiary and Upper Cretaceous aquifer systems are the uppermost units of the Northern Great Plains aquifer system (figs. 1, 2). These aquifer systems supply most freshwater used for domestic, stock, agricultural, and industrial purposes in the Williston Basin. Because most groundwater used in the study area is withdrawn from these three aquifer systems, they are described in greater detail herein than underlying aquifers/aquifer systems. The deeper Lower Cretaceous (sandstones), upper Paleozoic (sand stones and carbonate rocks), and lower Paleozoic (sandstones and carbonate rocks) aquifers/aquifer systems (fig. 2) are used rarely and undeveloped in most of the Williston Basin because of either uneconomical drilling depths, poor groundwater qual ity unsuitable for most uses without treatment, or both. Imme diately outside of the Williston Basin, the Lower Cretaceous aquifer system and upper and lower Paleozoic aquifers are used where present at economical drilling depths, and where the quality of the groundwater is acceptable for use. Most-Used Hydrogeologic Units Thamke and others (2014) constructed a hydrogeologic framework that defined and described the three uppermost principal aquifer systems in the Williston Basin for the United States and Canada, placing emphasis on the lower Tertiary and Upper Cretaceous aquifer systems (fig. 4). This frame work included a detailed description of the lithostratigraphic and hydrogeologic units composing three aquifer systems as shown in figures 4-8 and described in table 1. A three-dimen sional representation of these aquifer systems in the Williston Basin is shown in figure 5. The glacial, lower Tertiary, and Upper Cretaceous aqui fer systems are hydraulically separated from all underlying Northern Great Plains aquifer system aquifers/aquifer systems by a confining unit composed primarily of 800 to more than 3,000 feet (ft) of low-permeability Upper Cretaceous marine shale (identified herein as the "Upper Cretaceous confining unit," composed of strata in the Pierre Shale through Mowry Shale; fig. 2). The bowl-shaped structure of the Williston Basin causes the bedrock aquifer units to become exposed (crop out) in a pattern where the older rocks of the Upper Cre taceous aquifer system crop out around the outer margins of the basin and the younger rocks of the lower Tertiary aquifer system crop out in the center of the basin.
8 Potential Effects of Energy Development, Williston Basin—Water Resources A′ A′ A Hydrogeologic unit (fig. 2) 6,000 3,000 −3,000 −6,000 −9,000 −12,000 −13,500 EXPLANATION VERTICAL SCALE GREATLY EXAGGERATED 150 MILES 150 KILOMETERS Missouri River Bighorn Mountains Red River of the North General direction of groundwater flow Fault—Arrows show general direction of movement Brine area—Dissolved-solids concentration in groundwater is greater than 100,000 milligrams per liter Lower Tertiary aquifer system Upper Cretaceous aquifer system Upper Cretaceous confining unit Lower Cretaceous aquifer Jurassic rocks Triassic rocks Pennsylvanian-Permian rocks Pennsylvanian aquifer system Mississippian rocks (confining unit) Madison aquifer Mississippian rocks, including Bakken Formation Devonian rocks—Lower part of the Bakken Formation exists in the upper part of this unit. The Three Forks Formation underlies the Bakken Formation Silurian rocks Cambrian-Ordovician aquifer system Precambrian crystalline rocks (lower boundary of the Northern Great Plains aquifer system) Jurassic-TriassicPermian confining unit Devonian to Silurian aquifers and confining units Glacial aquifer system FEET SOUTHWEST NORTHWEST NAVD 88 Modified from Downey and Dinwiddie, 1988 Figure 3. Diagrammatic hydrogeologic cross-section A-A' through part of the Northern Great Plains aquifer system (modified from Downey and Dinwiddie, 1988). Line of section shown in figure 1.
Groundwater Resources 9 Bighorn Mountains Black Hills uplift Laramie Mountains Hartville uplift Porcupine dome Miles City Cedar Creek anticline arch F Nesson an ticli ne Turtle Mountains P o p a r Ri e r 45.78° N, 108.50° W B′ B′ B Casper Billings Rapid City Bismarck Base modified from U.S. Geological Survey and other Federal digital data, various scales North American Lambert Conformal Conic projection North American Datum of 1983 EXPLANATION Glacial aquifer system Upper Fort Union aquifer Middle Fort Union hydrogeologic unit Lower Fort Union aquifer Upper Hell Creek hydrogeologic unit Lower Hell Creek aquifer Fox Hills aquifer Lower Tertiary aquifer system Upper Cretaceous aquifer system Anticline or arch Fault Extent of total estimated Williston Basin control volume for water balance (table 2) Cross section B -B( ׳fig. 6) Geologic structures modified from Peterson (1984) and Love and Christiansen (1985) Hydrogeologic units from Thamke and others (2014) 100° 102° 104° 106° 48° 46° 44° 108° NEBRASKA 100 KILOMETERS 100 MILES UNITED STATES WYOMING MONTANA NORTH DAKOTA SOUTH DAKOTA CANADA MANITOBA SASKATCHEWAN Peerless Plateau POWDER RIVER BASIN WILLISTON BASIN Figure 4. Geographic extent of the glacial, lower Tertiary, and Upper Cretaceous aquifer systems and corresponding hydrogeologic units within and around the Williston Basin, and the cross-section B-B', United States and Canada.
10 Potential Effects of Energy Development, Williston Basin—Water Resources North American Lambert Conformal Conic projection North American Datum of 1983 EXPLANATION 100°00' 102°30' 105°00' 107°30' 47°30' 45°00' NAVD 88 (0) −6,000 −3,000 3,000 6,000 9,000 1,000 1,000 1,250 1,250 1,500 1,500 1,750 1,750 2,000 2,000 2,250 2,250 2,500 2,500 2,750 2,750 VERTICAL EXAGGERATION ×20 Upper Fort Union aquifer Middle Fort Union hydrogeologic unit Lower Fort Union aquifer Upper Hell Creek hydrogeologic unit Hydrogeologic units from Thamke and others (2014) Lower Hell Creek aquifer (combined with the Fox Hills in the Powder River Basin) Fox Hills aquifer (combined with the lower Hell Creek in the Powder River Basin) POWDER RIVER BASIN POWDER RIVER BASIN WILLISTON BASIN WILLISTON BASIN Structure contour—Shows altitude of top of basal confining unit. Contour interval 250 feet. Datum is North American Vertical Datum of 1988 (NAVD 88) 2,750 2,750 1,500 1,500 Miles City arch Miles City arch Cedar Creek anticline Cedar Creek anticline FEET Glacial aquifer system Lower Tertiary aquifer system Upper Cretaceous aquifer system Nesson anticline Altitude, in feet above or below NAVD 88 Figure 5. Generalized cross section showing three-dimensional framework of the glacial, lower Tertiary, and Upper Cretaceous aquifer systems in the Williston Basin (modified from Thamke and others, 2014).
Groundwater Resources 11 B′ B SOUTHWEST POWDER RIVER BASIN WILLISTON BASIN Miles City arch Cedar Creek anticline Lake Sakakawea VERTICAL SCALE IS 145X THE HORIZONTAL SCALE NAVD 88 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 FEET Turtle Mountains NORTHEAST EXPLANATION Glacial aquifer system Upper Fort Union aquifer Middle Fort Union hydrogeologic unit Lower Fort Union aquifer Upper Hell Creek hydrogeologic unit Lower Hell Creek aquifer Fox Hills aquifer Lower Tertiary aquifer system Upper Cretaceous aquifer system 100 KILOMETERS 100 MILES Nesson anticline Hydrogeologic units from Thamke and others (2014) Modified from Long and others, 2014 Figure 6. Hydrogeologic cross-section B-B' showing the glacial, lower Tertiary, and Upper Cretaceous aquifer systems in the Williston Basin (modified from Long and others, 2014). Line of section shown in figure 4.
12 Potential Effects of Energy Development, Williston Basin—Water Resources Base from U.S. Geological Survey digital data, 2013, 1:1,000,000 North American Lambert Conformal Conic projection North American Datum of 1983 EXPLANATION 47°30' 45°00' NEBRASKA 100 KILOMETERS 100 MILES UNITED STATES WYOMING MONTANA NORTH DAKOTA SOUTH DAKOTA CANADA Glacial aquifer system thickness, in feet Less than or equal to 50 Greater than 50 to 100 Greater than 100 to 300 Greater than 300 to 756 107°30' 102°30' 105°00' 100°00' Upper Fort Union aquifer Middle Fort Union hydrogeologic unit Lower Fort Union aquifer Upper Hell Creek hydrogeologic unit Lower Hell Creek aquifer Fox Hills aquifer Hydrogeologic units from Thamke and others (2014) Lower Tertiary aquifer system Upper Cretaceous aquifer system Approximate geographic extent of the glacial aquifer system Williston Basin boundary Figure 7. Thickness of the glacial aquifer system in and near the Williston Basin (modified from Thamke and others, 2014).
Groundwater Resources 13 1,000 1,000 4,000 5,000 6,000 3,000 2,000 2,000 7,000 1,000 1,000 1,000 1,000 2,000 2,000 2,000 2,000 1,000 1,000 2,000 2,000 1,000 1,000 2,000 1,000 1,000 2,000 2,000 1,000 1,000 2,000 2,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 2,000 2,000 2,000 2,000 1,500 1,500 1,500 1,500 1,500 1,500 1,500 1,500 1,500 1,500 1,500 1,500 1,000 1,000 Base from U.S. Geological Survey digital data, 2013, 1:1,000,000 North American Lambert Conformal Conic projection North American Datum of 1983 EXPLANATION 47°30' 45°00' NEBRASKA 100 KILOMETERS 100 MILES UNITED STATES WYOMING MONTANA NORTH DAKOTA SOUTH DAKOTA CANADA MANITOBA SASKATCHEWAN 107°30' 102°30' 105°00' 100°00' Combined lower Tertiary and Upper Cretaceous aquifer system thickness, in feet 8,500 Line of equal thickness—Interval 1,000 feet Line of equal thickness in the Williston Basin—Interval 500 feet Geographic extent of combined lower Tertiary and Upper Cretaceous aquifer systems Williston Basin boundary 1,000 Modified from Thamke and others, 2014 Figure 8. Thickness of the combined lower Tertiary and Upper Cretaceous aquifer systems in the Williston Basin (modified from Thamke and others, 2014).
14 Potential Effects of Energy Development, Williston Basin—Water Resources Glacial Aquifer System The glacial aquifer system overlies parts of the lower Ter tiary and Upper Cretaceous aquifer systems in the northeastern part of the Williston Basin (figs. 3-6; Thamke and others, 2014). The glacial aquifer system consists of Quaternary-age (fig. 2) unconsolidated till, silt, clay, outwash sand and gravel, and occasional cobbles and boulders deposited by continen tal glaciers. Estimated glacial aquifer system volume in the Williston Basin (United States and Canada) is 150 trillion ft³ (table 1). Widely differing lithologic characteristics result in an aquifer/aquifer system that is characterized by multiple disconnected and locally productive sand and gravel aquifers buried beneath till and other glacial or surficial deposits, and that typically is in preglacial valleys that exist in the buried bedrock surface (Paulson, 1983; Winter and others, 1984; Kehew and Boettger, 1986; Cummings and others, 2012; Pugin and others, 2014). These productive buried sand and gravel aquifers are sources of water for thousands of shal low wells in the Williston Basin. Thickness of glacial aquifer system deposits in the Williston Basin varies locally; maxi mum thickness is estimated to be 756 ft, and the deposits are thickest in northern and north central North Dakota (fig. 7). Hydraulic characteristics of the glacial aquifer system differ widely because of highly variable lithology, but the deposits can be highly productive in places (table 1). Lower Tertiary Aquifer System The lower Tertiary aquifer system in the Williston Basin consists of the upper and lower Fort Union aquifers separated by the middle Fort Union hydrogeologic unit (figs. 2, 4-6; Thamke and others, 2014). The aquifer system is estimated to be as thick as 2,246 ft and has a volume of about 1,002 tril lion ft³ (table 1). Rocks composing the lower Tertiary aquifer system represent many depositional environments, most com monly continental and nearshore (fluvial, deltaic, tidal, and barrier-shoreface) depositional environments; and less com monly, marine depositional environments (Flores and Bader, 1999; Flores and others, 1999). Because of spatially variable lithology reflective of these many depositional environments, the middle Fort Union and upper Hell Creek hydrogeologic units may act as confining units in some areas and aquifers in other areas. The upper Fort Union aquifer (figs. 2, 4-7) is composed of as much as 1,917 ft (table 1) of massive, crossbedded, lightyellow to light-yellow-gray sandstone, sandy mudstone, gray shale, carbonaceous shale, and thick coal beds and associ ated clinker deposits (permeable rocks created by the natural burning of coal beds). Rocks composing the upper Fort Union aquifer generally are light-colored compared to the underlying middle Fort Union hydrogeologic unit. In the Williston Basin, the upper Fort Union aquifer is present in Montana and North Dakota but not in South Dakota (fig. 4; Thamke and others, 2014). The specific formations or formation members that compose the aquifer are shown in figure 2, and their properties are described in table 1. Thickness of the upper Fort Union aquifer is greatest in the central part of the Williston Basin, near the Montana/North Dakota border, and thins at the edges where erosion has removed most of the unit (fig. 6). Because of geographic occurrence at or near land surface (fig. 4) and greater permeability throughout much of the Williston Basin, the upper Fort Union aquifer is the most used aquifer of the lower Tertiary aquifer system. The middle Fort Union hydrogeologic unit (figs. 2, 4-7; Thamke and others, 2014) is present throughout the central part of the Williston Basin but thins toward the northeast and pinches out along the northeastern one-third of the basin (figs. 5, 6). The specific formations or formation members that compose the aquifer are shown in figure 2, and their proper ties are described in table 1. Composed of as much as 520 ft of alternating beds of sandstone, siltstone, mudstone, claystone, and lignite, rocks in the middle Fort Union hydrogeologic unit generally are finer-grained and darker-colored than rocks in the overlying upper Fort Union Formation and underlying lower Fort Union Formation. Because of spatially variable lithology, the middle Fort Union hydrogeologic unit may act as a confining unit in some areas and as an aquifer in other areas. Present throughout most of Williston Basin, the lower Fort Union aquifer (figs. 2, 4-7) is composed of as much as 668 ft (table 1) of yellow-weathering sandstones and lightgray-weathering sandy mudstones interfingering with alternat ing brown and gray beds of sandstone, siltstone, claystone, mudstone, and lignite. The specific formations or formation members that compose the aquifer are shown in figure 2, and selected physical properties are described in table 1. Upper Cretaceous Aquifer System The Upper Cretaceous aquifer system is the deepest and most areally extensive of the three most-used aquifer sys tems underlying the Williston Basin (figs. 2, 3-7). From top to bottom, the Upper Cretaceous aquifer system consists of the upper Hell Creek hydrogeologic unit, lower Hell Creek aquifer, and Fox Hills aquifer (figs. 2, 4-7; Thamke and oth ers, 2014). All three Upper Cretaceous hydrogeologic units are present throughout most of the Williston Basin (figs. 4-6). Estimated volume of the Upper Cretaceous aquifer system is 1,005 trillion ft3 in the Williston Basin (table 1). The upper Hell Creek hydrogeologic unit (figs. 2, 4-7) is composed of as much as 738 ft (table 1) of alternating layers of gray and brown mudstone, siltstone, sandstone, and sparse lignite beds in the upper part of the Hell Creek Formation deposited by meandering channels with point bars and channel plugs. Lithology in the underlying lower part of the Hell Creek Formation is similar, so the upper Hell Creek hydrogeologic unit is defined where the percentage of sandstone is generally smaller. Like the middle Fort Union hydrogeologic unit, the upper Hell Creek hydrogeologic unit may act as a confining unit in some areas and as an aquifer in other areas because of spatially variable lithology.
Groundwater Resources 15 The lower Hell Creek aquifer (figs. 2, 4-7) consists of rocks in the lower part of the Hell Creek Formation that were deposited as the basal part of a Late Cretaceous continental clastic wedge that extended from the Rocky Mountains to the central plains and was deposited in the swamps and flood plains on or near a deltaic front adjacent to the Late Creta ceous inland sea (Murphy, 2001). Channel deposits and ero sional surfaces are common in the lower Hell Creek Formation comprising the aquifer (Flores, 1992). Maximum thickness of the lower Hell Creek aquifer is as much as 548 ft in the Wil liston Basin (fig. 6; table 1). Present throughout the Williston Basin (fig. 4), the Fox Hills aquifer consists of the Fox Hills Sandstone and is the deepest hydrogeologic unit of the Upper Cretaceous aquifer system (figs. 2, 5-7). As much as 422 ft (table 1) of interbed ded mudstone, siltstone, and sandstone compose the Fox Hills aquifer; these rocks were deposited in shore, nearshore, and delta plain environments during the final stage of the Late Cretaceous inland sea (Cvancara, 1976; Murphy, 2001). Groundwater Budget and Flow System Groundwater recharge to the glacial, lower Tertiary, and Upper Cretaceous aquifer systems (figs. 1, 3-7) is from direct infiltration of rainfall and snowmelt on outcrop areas (precipitation recharge), streamflow losses to underlying units (stream infiltration), infiltration of irrigation waters (irrigation recharge), and groundwater inflow from the Powder River Basin (table 2; Whitehead, 1996; Aurand, 2013; Bednar, 2013; Long and others, 2014). Total estimated recharge to these aquifer systems in the Williston Basin is 4,560 cubic feet per second (ft3/s) (table 2; Long and others, 2014). Stream infiltration and precipitation recharge composed most of the recharge, accounting for 71 and 26 percent of total recharge, respectively; irrigation recharge and groundwater inflow accounted for only 2 and less than 1 percent of total recharge, respectively (table 2; Long and others, 2014). Estimated mean precipitation recharge for the Williston Basin for 1981 through 2005 was 0.18 inch per year (in/yr) (1,190 ft³/s; table 2) or about 1.1 percent of precipitation (Long and others, 2014). Water in the lower Tertiary and Upper Cretaceous aquifer systems primarily is under confined conditions except along basin margins and in aquifers in the upper part of the hydrogeologic units, which are characterized by topographi cally controlled local flow systems (Whitehead, 1996; Long and others, 2014; Thamke and others, 2014). Depth to the water table in unconfined parts of the lower Tertiary and Upper Cretaceous aquifer systems ranges from 0 to 823 ft (mean=97 ft) (Long and others, 2014). The water table is shal lowest near streams and deepest in upland areas. Horizontal hydraulic gradients are largest in the upper Fort Union aquifer as indicated by the closeness of the contours, and smallest in the Upper Cretaceous aquifer system (fig. 9). Where aquifers in the lower Tertiary and Upper Cretaceous aquifer systems are covered by the glacial aquifer system or unconsolidated alluvial deposits, water can percolate downward through these deposits to the bedrock aquifers. South of the glacial aquifer system where the upper Fort Union aquifer is unconfined, the potentiometric surface is topographically controlled and gener ally follows the orientation of land-surface slopes, resulting in localized groundwater flow from topographically high areas toward stream valleys (fig. 9; Thamke and others, 2014; Long and others, 2014). Potentiometric surfaces in the other lower Tertiary and Upper Cretaceous hydrogeologic units indicates Table 2. Estimated average groundwater recharge and discharge components for 1981 through 2005 for the combined glacial, lower Tertiary, and Upper Cretaceous aquifer systems within the Williston Basin control volume area (modified from Long and others, 2014). less than; NA, not applicable] Recharge or discharge component Estimated Williston Basin control volume (fig. 4) Period of record Cubic foot per second Percentage of total Groundwater recharge Precipitation recharge 1,190 1981-2005 Stream infiltration 3,260 1900-2005 Irrigation recharge 1981-2005 Groundwater inflow from the Powder River Basin
NA Total recharge 4,560 NA Groundwater discharge Discharge to streams 4,420 1900-2005a Groundwater withdrawal 1981-2005 Discharge to reservoirs
NA Total discharge 4,560 NA aData through 2011 were used for about 4 percent of the streamgages.
16 Potential Effects of Energy Development, Williston Basin—Water Resources Milk River Beaver Creek Keya Paha River Souris River Souris River Long Creek Lake Sakakawea e d ar re ek Nio bra ra Ri ve r Che yen ne Riv er O'Fa o n
Cr ee k So ur is
R e r Fort Peck Lake Lake Oahe B o e d e r
r e ek A s s inibo in e R ver M o os e Mou nta n
Cr ee k Fren chma n River B g M u d d y
r e e k Poplar
R er Mis sou ri R er Little Mu dd y
R e r Red wa te r Ri ve r Ye llow ston e R er Mussels he ll Riv e r Big ho rn R ive r Rose bud Cre e k Tongue Rive r Belle F ou rc he
R e r Little Powder R ive r Antelope C r e e k N o r t h
P a t t e R iver S h e y e n n e
Rive r Knife River Little M s s ou r
R er Miss o u r
R e r Hea rt
R e r Can no nb al Ri ve r Gr an d R e r Mo re au R er Okoboj o C re ek Me di ne K no
r e e k he rr y Cr ee k B a d Ri ve r Ch e y e nne
R e r Old Wives Lake P ow der Ri ver UNITED STATES WYOMING SOUTH DAKOTA MONTANA NORTH DAKOTA CANADA MANITOBA SASKATCHEWAN Cedar Creek anticline Miles City arch 100°00' 102°30' 105°00' 107°30' 50°00' 47°30' 45°00' Base modified from U.S. Geological Survey and other Federal digital data, various scales North American Lambert Conformal Conic projection North American Datum 1983 EXPLANATION 100 MILES 100 KILOMETERS Upper Fort Union aquifer Middle Fort Union hydrogeologic unit Lower Fort Union aquifer Upper Hell Creek hydrogeologic unit Lower Hell Creek aquifer Fox Hills aquifer Lower Tertiary aquifer system Upper Cretaceous aquifer system Hydrogeologic units from Thamke and others (2014) Glacial aquifer system Figure 9. Potentiometric surfaces of the upper Fort Union aquifer, lower Fort Union aquifer, and Upper Cretaceous aquifer system in the Williston Basin (modified from Thamke and others, 2014). An interactive version of this map is available for download at ://doi.org/10.3133/sir20175070C.
Groundwater Resources 17 groundwater flow generally is from the west and southwest toward the east, where the groundwater regionally discharges to streams (fig. 9). Potentiometric surfaces for the upper and lower Fort Union aquifers are similar in the northern and western parts of the Williston Basin, except for less relief for the lower Fort Union aquifer, indicating probable hydraulic connection between the two aquifers (fig. 9). The glacial, lower Tertiary, and Upper Cretaceous aquifer systems discharge in the form of groundwater discharge to streams and reservoirs; and withdrawals from wells for domestic, irrigation, public-supply, and self-supplied industrial uses (groundwater withdrawal) (Whitehead, 1996; Aurand, 2013; Bednar, 2013; Long and others, 2014). Most of this groundwater discharge is to streams, representing an estimated 97 percent or 4,420 ft3/s of the total discharge for the units in the Williston Basin (table 2; Long and others, 2014). Several studies have documented local groundwater-level declines because of flowing artesian wells; these wells flow continuously because of hydrostatic pressure. Declines from flowing artesian wells open to the Fox Hills and lower Hell Creek aquifers have been noted near the Yellowstone, Little Missouri, and Knife Rivers in Montana and North Dakota (not shown; Smith and others, 2000; Honeyman, 2007a, b, c; Fischer, 2013). Locally, flowing artesian wells that discharge water from the Upper Cretaceous aquifer system may allow leakage into the overlying lower Tertiary aquifer system because of inadequate sealing or corrosion of these wells (Fischer, 2013; Long and others, 2014). Other Hydrogeologic Units Other hydrogeologic units are described in this section. These include the Upper Cretaceous confining unit, Lower Cretaceous aquifer system, Jurassic-Triassic-Permian confin ing unit, and Paleozoic aquifers/aquifer systems. Upper Cretaceous Confining Unit A substantial confining unit underlies the Upper Creta ceous aquifer system and overlies the Lower Cretaceous aqui fer system throughout the Williston Basin (figs. 2, 3). The spe cific lithostratigraphic units that compose the unit are shown in figure 2 (Downey, 1986; Downey and Dinwiddie, 1988; Thamke and others, 2014). Dark, clayey, low-permeability marine shale composes most of the confining unit. Thickness of the confining unit ranges from 800 to more than 3,000 ft (Anna, 1986; Downey, 1986; Downey and Dinwiddie, 1988; fig. 3). Although shale composes most of the unit, interbedded sandstone beds within the shales (Tourtelot, 1962; Carlson, 1979; Murphy, 2001) can contain local aquifers (Downey, 1986; Downey and Dinwiddie, 1988; Busby and others, 1995). In addition, the Pierre Shale in northern North Dakota can act locally as an aquifer where near-surface fracture zones have developed (Downey, 1973). Lower Cretaceous Aquifer System Present throughout the Williston Basin, the Lower Cretaceous aquifer system (fig. 3) consists primarily of watersaturated and permeable sandstone beds containing aquifers interbedded with finer-grained rocks such as siltstone and shale. The specific lithostratigraphic units that compose the individual Lower Cretaceous aquifers and confining units of the aquifer system are shown in figure 2 (Dyer and Goehring, 1965; Butler, 1984; Case, 1984; Downey, 1984a, 1984b, 1986; Peter, 1982; Schoon, 1984; Downey and Dinwiddie, 1988; Busby and others, 1995; Whitehead, 1996). Combined thick ness of all Lower Cretaceous rocks in the Williston Basin gen erally ranges from about 100 to 500 ft (fig. 6; Downey, 1986). Many investigators divide the Lower Cretaceous aquifer system into the Newcastle or Dakota aquifers (composed of the Newcastle Formation/Sandstone or the Dakota Formation/ Sandstone [older alternative name for rocks in parts of North Dakota and South Dakota equivalent to the Newcastle Forma tion], respectively) and the Inyan Kara aquifer (composed of sandstone beds in the Inyan Kara Formation in North Dakota, Fall River and Lakota Formations of the Inyan Kara Group in South Dakota, and Fall River and Kootenai Formations in eastern Montana; fig. 2). The Lower Cretaceous aquifer system is also commonly identified as the Dakota aquifer or aquifer system, or Dakota-Newcastle aquifer system (fig. 2; Bredehoeft and others, 1983; Butler, 1984; Case, 1984; Peter, 1982; Wartman, 1984). Where present, the Skull Creek Shale is classified as a confining unit that separates the two aquifers (fig. 2). Where the Skull Creek Shale pinches out in central and eastern North Dakota and South Dakota, the two aquifers merge into a single aquifer. The Lower Cretaceous (Dakota) aquifer system has been studied extensively because of the large quantities of water that can be developed from the aqui fer system in some areas (primarily outside of the Williston Basin), and because it is considered to be a classic example of an artesian aquifer system (for example, Bredehoeft and oth ers, 1983; Leonard and others, 1984). Lower Cretaceous aquifers are unused as sources of water in much of the Williston Basin because of the depth of these resources (as much as 10,000 ft in the central part of the basin), saline waters, and availability of shallower groundwa ter; however, water is withdrawn for domestic, municipal, and agricultural uses where the aquifers are present at shallower depths, and waters are fresher adjacent to and immediately outside the western and southwestern margin of the Willis ton Basin (for example, Bredehoeft and others, 1983; Butler, 1984; Case, 1984; Wartman, 1984). In these areas, wells are completed in the aquifers because drilling depths are economi cal, and waters are fresh or slightly saline because of proxim ity to aquifer recharge areas. Many wells constructed in these areas flow in response to artesian pressure. In parts of the Williston Basin where petroleum is extracted from deeper formations with saline and briny waters, Lower Cretaceous formations historically have been,
18 Potential Effects of Energy Development, Williston Basin—Water Resources and continue to be, used as reservoirs for injection of liquid wastes generated as part of the production process (Wartman, 1984; Kurz and others, 2016; Scanlon and others, 2016). Most (93 percent or more by volume) of the produced waters associ ated with the Bakken oil play disposed of through injection are injected into the Inyan Kara Formation within the Lower Cretaceous (Dakota) aquifer system in western North Dakota where total dissolved solids (TDS) ranges from 10,000 to 30,000 milligrams per liter (mg/L) (Kurz and others, 2016; Bader, 2017; Ge and others, 2018). The Dakota aquifer system is a favorable target of disposal because of suitable injection characteristics and because aquifer depth is about 1,500 to 2,000 ft shallower than other saline aquifers suitable for pro duced water disposal (Kurz and others, 2016). Infiltration on outcrops along the flanks of structural uplifts adjacent to the basin recharges the Lower Cretaceous aquifer system. Additional potential recharge to the Lower Cretaceous aquifer system originates from either upward movement of water from the underlying Paleozoic aquifers in areas where confining units are either thin or absent (fig. 10; Kolm and Peter, 1984; Butler, 1984; Case, 1984; Downey and Dinwiddie, 1988), or downward movement of water to the aquifer from or through the overlying Upper Cretaceous confining unit (Pierre Shale) through fractures (Neuzil and others, 1982; Peter, 1982). Regional groundwater movement in the Lower Cretaceous aquifer system is towards the east and northeast from recharge areas along the flanks of struc tural uplifts in the western and southwestern Williston Basin (for example, Black Hills uplift) (fig. 10; Butler, 1984; Case, 1984; Lobmeyer, 1985; Downey and Dinwiddie, 1988; Bachu and Hitchon, 1996). The Lower Cretaceous aquifer system discharges primarily through (1) lateral leakage to adjacent hydrogeologic units (figs. 3, 10), (2) upward leakage to over lying hydrogeologic units in areas in eastern South Dakota and North Dakota (figs. 3, 10), (3) withdrawals from wells, (4) artesian flow from unused wells, and (5) leakage from improperly abandoned and sealed wells (Butler, 1984; Case, 1984; Lobmeyer, 1985; Downey and Dinwiddie, 1988; Busby and others, 1995; Bachu and Hitchon, 1996). Freshwater in the Lower Cretaceous aquifer system is present in the Williston Basin only in a small area north and east of the Black Hills uplift (fig. 11). Upward leakage of highly mineralized water from underlying hydrogeologic units may contribute substantially to the salinity (Butler, 1984; Wartman, 1984; Busby and others, 1995). Lower Cretaceous aquifers contain slightly saline water (dissolved-solids con centration ranging from greater than 1,000 to 3,000 mg/L) throughout most of South Dakota and a large area in south eastern North Dakota (fig. 11). The aquifers contain saline waters (dissolved-solids concentration ranging from greater than 3,000 to 10,000 mg/L) in most of the rest of the Williston Basin area, except in the deep parts in northeastern Montana and northern and northwestern North Dakota (fig. 11; Busby and others, 1995) where the aquifers contain very saline and briny waters (dissolved-solids concentration ranging from more than 10,000 to more than 35,000 mg/L. The spatial extent of dissolved solids concentrations ranging from 10,000 to more than 35,000 mg/L were not mapped at the time of this publication (Kurz and others, 2016), and were depicted as only greater than 10,000 mg/L in figure 11. Jurassic-Triassic-Permian Confining Unit Jurassic- to Permian-age lithostratigraphic units compose a regional confining unit in the Williston Basin, and specific formations that compose the unit are identified in figure 2 (Downey, 1986; Downey and Dinwiddie, 1988; Bachu and Hitchon, 1996). Lithology of the confining unit represents many depositional environments, including sandstone, silt stone, shale, limestone, and evaporates. Because of predomi nantly fine-grained lithology and, in particular, the widely present interbedded evaporates/salts, this confining unit pre vents vertical water movement between all overlying Lower Cretaceous and other younger units (fig. 2) and all underly ing Paleozoic units (fig. 2) in most of the Williston Basin (Downey, 1986; Downey and Dinwiddie, 1988; Busby and others, 1995). Locally, parts of the Swift, Rierdon, and Piper Formations (fig. 2) may be sufficiently permeable to yield water to wells and be classified as aquifers (Whitehead, 1996). Paleozoic Aquifers/Aquifer Systems Studies of the Williston Basin in the United States and Canada have identified regional bedrock aquifers/aquifer sys tems in the upper and lower Paleozoic lithostratigraphic units below the Jurassic-Triassic-Permian confining unit (figs. 2, 3; Downey, 1984a, b, 1986, 1987; Downey and Dinwiddie, 1988; Busby and others, 1995; Bachu and Hitchon, 1996; Whitehead, 1996; Benn and Rostron, 1998). Upper and lower Paleozoic lithostratigraphic units are of variable composition throughout the Williston Basin, and many of the units or parts of the units function as aquifers, petroleum reservoirs, or both; however, few water wells are completed in Paleozoic aqui fers in the Williston Basin primarily because of deep burial throughout most geographic extent and availability of ground water from shallower aquifers/aquifer systems with sufficient quantity and quality of water for most uses. Where deeply buried, Paleozoic aquifers typically contain very saline waters, and commonly contain a spatially variable mixture of fluids including water, brine, oil, and natural gas. Upper Paleozoic Units Upper Paleozoic aquifers and confining units are com posed of generally deeply buried Permian- to Mississippianage lithostratigraphic units (figs. 2, 3). Water-saturated and permeable marine sandstone in the Permian- and Pennsyl vanian-age Minnelusa Group or Formation and stratigraphic equivalents compose the Pennsylvanian aquifer system in the Williston Basin (fig. 2; Downey, 1984a, 1986; Downey and Dinwiddie, 1988; Busby and others, 1995). The aquifer system is confined from above by the Jurassic-Triassic-Permian
Groundwater Resources 19 300 MILES 300 KILOMETERS 95° 100° 105° 110° 50° 45° Fargo Casper Pierre Pierre Helena Cheyenne Billings Bismarck Bismarck Rapid City Sioux Falls Great Falls MANITOBA SASKATCHEWAN ONTARIO ALBERTA MINNESOTA NORTH DAKOTA MONTANA IDAHO WYOMING NEBRASKA COLORADO UTAH IOWA Cedar Lake LAKE MANITOBA LAKE MANITOBA Lake Winnipegosis Lake Winnipegosis Fort Peck Lake Lake Sakakawea Lake Sakakawea Lake Oahe Yellowstone Lake SOUTH DAKOTA
M is so ur R ive r
M is so ur R ive r Base from U.S. Geological Survey digital data, variously dated, various scales Albers Equal-Area Conic projection Standard parallels 29°30' N. and 45°30' N. Central meridian 96°00' W. North American Datum of 1983 Lake Sharpe Lake Sharpe EXPLANATION General area of recharge to the Lower Cretaceous aquifer system originating as precipitation on outcrops General area of discharge to overlying glacial deposits, including the glacial aquifer system General area of discharge as upward leakage to other overlying rocks of Cretaceous-age hydrogeologic units and as outflow through wells General area of recharge as interformational flow from Mississippian- and Pennsylvanian-age hydrogeologic units Approximate limit of the Lower Cretaceous aquifer system General direction of groundwater flow in the Lower Cretaceous aquifer system Northern Great Plains aquifer system boundary (Whitehead, 1996)—Dashed where approximate Williston Basin boundary CANADA UNITED STATES M iss ou r River Y e low s t o ne R iver Y e low s t o ne R iver Grand Forks Red River of the Nort h LAKE WINNIPEG B A K HI S U P FT Figure 10. General areas of recharge to, discharge from, and groundwater flow in the Lower Cretaceous aquifer system in the Williston Basin and adjacent areas, United States and Canada (modified from Downey and Dinwiddie, 1988).
20 Potential Effects of Energy Development, Williston Basin—Water Resources MILES KILOMETERS 96° 100° 104° 108° 112° 116° 48° 46° 44° 42° Fargo Casper Pierre Helena Cheyenne Billings Bismarck Rapid City Sioux Falls Grand Forks Great Falls Base from U.S. Geological Survey digital data, variously dated, various scales Albers Equal-Area Conic projection Standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 NORTH DAKOTA MONTANA WYOMING Fort Peck Lake Lake Sakakawea Lake Oahe Yellowstone Lake SOUTH DAKOTA CANADA UNITED STATES Lake Sharpe Lake Francis Case
Miss o u r Ri ve r Y e o w st o n e R er Canyon Ferry Lake
Re d Rive r of th e N orth EXPLANATION Dissolved-solids concentration in water from the Lower Cretaceous aquifer system, in milligrams per liter 0 to 1,000 Greater than 1,000 to 3,000 Greater than 3,000 to 10,000 Greater than 10,000 No data Aquifers absent NEBRASKA UTAH IDAHO MINNESOTA Missouri River Northern Great Plains aquifer system boundary (Whitehead, 1996)—Dashed where approximate Williston Basin boundary B A K HI S U P FT B A K HI S U P FT Figure 11. Dissolved-solids concentrations in water from the Lower Cretaceous aquifer system in the Williston Basin (modified from Whitehead, 1996).
Groundwater Resources 21 confining unit and below by a confining unit composed of the Mississippian-age Big Snowy Group and the Charles Forma tion of the Madison Group (fig. 2). The Pennsylvanian aquifer system is mainly undeveloped as a source of water supply in the Williston Basin. Some produced water associated with the Bakken oil play is disposed of by injection into the Minnelusa Group or Formation (Kurz and others, 2016). Below the Charles Formation, water-saturated and perme able carbonate rocks (limestone and dolomite) in parts of the Mission Canyon and Lodgepole Limestones of the Madison Group compose the Madison aquifer in the Williston Basin (fig. 2; Downey, 1984a, 1986; Downey and Dinwiddie, 1988; Busby and others, 1995). Some studies also have indicated that the Madison Group likely can be divided into a series of fluid-bearing aquifers/reservoirs, in contrast to being mapped as a single aquifer (for example, Jensen and Rostron, 2006; Palombi, 2008). The Madison Group ranges in thickness from less than 200 ft along the eastern margin of the Williston Basin to as much as 2,800 ft in the deepest part in northwestern North Dakota and northeastern Montana (Busby and others, 1995). Porosity and permeability in the carbonate rocks that compose much of the Madison Group (and other Paleozoic units) varies substantially because of differing geological and hydrological processes (MacCary and others, 1983; Thayer, 1983; Downey, 1984a, 1986). The Madison aquifer is used as a source of water for many different uses outside of and near the Williston Basin, most notably in the Black Hills uplift area where the Madison aquifer is developed as a source of water for many different uses and has been extensively studied (for example, Carter and others, 2002). In much of the Williston Basin, the Madison Group is an important petroleum reservoir, and the geologic and hydrogeologic characteristics of the unit have been studied to understand fluid flow in relation to petro leum generation and accumulation (Downey and others, 1987; Peterson and MacCary, 1987; Gaber, 1992; Berg and others, 1994; DeMis, 1995; Toop and Tóth, 1995; Burrus and others, 1996; LeFever, 1998; Jensen and Rostron, 2006). Some pro duced water associated with the Bakken oil play is disposed of by injection into the Madison Group (Kurz and others, 2016). Lower Paleozoic Units Lower Paleozoic aquifers and confining units are com posed of generally deeply buried pre-Madison Group Missis sippian- to Cambrian-age lithostratigraphic units overlying the Precambrian basement (figs. 2, 3). Permeable zones in these units comprise aquifers, petroleum reservoirs, or both. Aquifers are composed primarily of permeable carbonate rocks (lime stone and dolomite) and sandstone, whereas confining units are composed primarily of shale, shaley carbonate rocks, evapo rates/salts, and filled breccias (Downey, 1984a, 1986, 1987; Downey and Dinwiddie, 1988; Busby and others, 1995; Bachu and Hitchon, 1996; Benn and Rostron, 1998; Alkalali, 2002; Khan and Rostron, 2004; Palombi, 2008). Because of spatially variable lithology, lower Paleozoic lithostratigraphic/hydro geologic units may act as confining units in some areas and aquifers in other areas. Although these units have little watersupply development potential in most of the Williston Basin because of deep burial and predominantly saline and briny waters, considerable effort has been made to understand fluid flow and hydrochemistry in the lower (and upper) Paleozoic aquifers and confining units, or both because they contain exten sive mineral and energy resources. Description of these numer ous studies is beyond the scope of this summary, but the reader is referred to numerous studies examining these characteristics in Paleozoic aquifers in the Williston Basin (Hanshaw and oth ers, 1978; Downey, 1984a, b, 1986, 1987; Leonard and others, 1984; Downey and others, 1987; Hannon, 1987; Downey and Dinwiddie, 1988; Busby and others, 1991, 1995; Berg and others, 1994; DeMis, 1995; Toop and Tóth, 1995; Bachu and Hitchon, 1996; Burrus and others, 1996; Benn and Rostron, 1998; LeFever, 1998; Iampen and Rostron, 2000; Alkalali, 2002; Margitai, 2002; Rostron and Holmden, 2003; Jensen and Rostron, 2006; Khan and Rostron, 2004; Palombi and Rostron, 2006; Palombi, 2008; Anna, 2013). In addition, lower Paleozoic hydrogeologic units continue to be studied because of potential use of the deep saline and briny aquifers as reservoirs and the associated confining units as geologic reservoir traps/seals for disposal of nuclear waste (Sandberg, 1962; Brunskill, 2006) and anthropogenic carbon dioxide (CO2; Whittaker and others, 2002, 2004; Whittaker and Gilboy, 2003; Khan and Rostron, 2004; Fisher and others, 2005; Sorensen and others, 2009; Houseworth and others, 2011; Liu and others, 2014). A confining unit composed of the Mississippian- and Devonian-age Bakken and Devonian-age Three Forks Forma tions underlies the Madison aquifer and separates the overlying upper Paleozoic aquifers from the underlying lower Paleozoic aquifers and confining units where present (fig. 2). The Bakken Formation is a petroleum source and reservoir that produces large volumes of petroleum, commonly in combination with the underlying Three Forks Formation (Pollastro and others, 2013). Most of the oil production from the Bakken Formation is from the middle member, an oil-bearing aquifer/ reservoir confined by the impermeable upper and lower members (Whittaker and others, 2004; Kreis and others, 2006; Jensen and Rostron, 2006; Palombi, 2008). Bakken Forma tion thickness is estimated to be as much as 160 ft in the U.S. part of the Williston Basin (LeFever, 2008). The Three Forks Formation underlies the Bakken Formation where present and consists of as much 270 ft of marine and nonmarine generally low-permeability mudstone, dolomite, and anhydrite (Bottjer and others, 2011). Some earlier investigators combined the Bak ken and Three Forks Formations with additional stratigraphi cally older and deeper Devonian and Silurian lithostratigraphic units into a much larger confining unit in the U.S. part of the Williston Basin (Downey, 1984a, b; Downey and others, 1987; Downey and Dinwiddie, 1988; Busby and others, 1995). More recent studies grouped the Bakken and Three Forks Formations without the additional Devonian and Silurian lithostratigraphic units into a single confining unit (Bachu and Hitchon, 1996; Benn and Rostron, 1998; Grasby and Betcher, 2002; Palombi, 2008) identified informally herein as the "Bakken-Three Forks
22 Potential Effects of Energy Development, Williston Basin—Water Resources confining unit" (fig. 2). Where present, the Bakken-Three Forks confining unit is a substantial regional confining unit that restricts fluid flow in overlying stratigraphically younger hydrogeologic units such as the upper Paleozoic aquifers/aqui fer systems from underlying lower Paleozoic aquifers/aquifer systems in much of the Williston Basin (Bachu and Hitchon, 1996; Benn and Rostron, 1998). Below the Bakken-Three Forks confining unit, all or parts of six Devonian- to Ordovician-age lithostratigraphic units of variable composition compose a series of alternating aquifers and confining units (fig. 2; Benn and Rostron, 1998; Alkalali, 2002; Grasby and Betcher, 2002; Palombi and Rostron, 2006; Palombi, 2008). Bachu and Hitchon (1996) grouped all aqui fers and confining units between the Bakken-Three Forks and Prairie Formation confining units into an aquifer system identi fied as the Devonian aquifer system. Many of these units are oil bearing in parts of the Williston Basin (Anna, 2013). Earlier hydrogeologic and hydrochemical studies completed primar ily to evaluate water-supply potential (Downey, 1984a, 1984b; Downey and Dinwiddie, 1988; Busby and others, 1995) and fluid flow in relation to petroleum systems (Downey and others, 1987; DeMis, 1995) grouped these units with the overlying Bakken and Three Forks Formations into a single thick regional confining unit (Bakken Formation to Stonewall Formation; fig. 2). Rocks composing aquifers in this stratigraphic sequence consist mainly of permeable carbonate rocks and less commonly permeable breccias, anhydrite, siltstone, and shale. Evaporites in parts of this stratigraphic sequence contribute substantially to the confining nature of parts of the lithostratigraphic units (Downey, 1986; Downey and Dinwiddie, 1988; Palombi, 2008). The combined thickness of all Silurian and Devonian rocks in the Williston Basin ranges from less than 500 to more than 3,000 ft (Busby and others, 1995). Similar to the overlying stratigraphic sequence, Cam brian- and Ordovician-age rocks below the Ordovician Stony Mountain Formation contain a series of alternating aquifers and confining units (fig. 2). Deposited as shoreward facies of a transgressive sea, rocks of Cambrian and Ordovician age consist primarily of marine shale, limestone, and sandstone. Combined thickness of Cambrian and Ordovician rocks ranges from less than 500 ft along the Williston Basin margins to as much as 2,000 ft in the deepest part of the basin (Downey and Dinwiddie, 1988). Earlier studies grouped the Cambrian and Ordovician rocks in the Stony Mountain to Deadwood Forma tion stratigraphic sequence into a single thick regional aquifer/ aquifer system identified as the Cambrian-Ordovician aquifer or aquifer system (fig. 2; Downey, 1984a, 1986; Downey and others, 1987; Downey and Dinwiddie, 1988; Busby and others, 1995); the basal aquifer system (Bachu and Hitchon, 1996); or, more broadly, the lower Paleozoic aquifers (Whitehead, 1996). Subsequent studies have subdivided the Cambrian-Ordovician aquifer into two aquifers (Red River and Cambrian-Ordovician aquifers) and two confining units (Stony Mountain and Win nipeg confining units) (fig. 2; Bachu and Hitchon, 1996; Benn and Rostron, 1998; Grasby and Betcher, 2002; Margitai, 2002; Rostron and Holmden, 2003; Palombi, 2008). The Red River aquifer, also known as the Yeoman aquifer, consists of perme able parts of the Ordovician Red River (Yeoman) Formation (MacCary and others, 1983; Benn and Rostron, 1998; Grasby and Betcher, 2002; Margitai, 2002; Whittaker and others, 2002, 2004; Whittaker and Gilboy, 2003; Palombi and Rostron, 2006; Palombi, 2008). The Red River Formation consists of a thick sequence of carbonate rocks (limestone and dolomite), and the unit is a major petroleum reservoir in the Williston Basin (Anna, 2013). Overlain by the Winnipeg Group or Formation confin ing unit and underlain by rocks of the Precambrian basement, the Cambrian-Ordovician aquifer is the basal aquifer of the Northern Great Plains aquifer system (fig. 2). Deeply bur ied in most of the Williston Basin, the Cambrian-Ordovician aquifer consists of siliciclastic rocks (sandstones) in the lower part of the Ordovician Winnipeg Group or Formation and the underlying Cambrian Deadwood Formation (fig. 2; Benn and Rostron, 1998; Grasby and Betcher, 2002; Margitai, 2002; Palombi, 2008). The sandstone composition of the CambrianOrdovician aquifer contrasts with all overlying lower Paleozoic aquifers composed primarily of carbonate rocks. Permeability of the sandstones composing the aquifer is reduced because of compaction from deep burial (Downey and Dinwiddie, 1988); nevertheless, the deeply buried Cambrian-Ordovician aquifer is considered to have sufficient permeability to possibly serve as a reservoir for disposal of anthropogenic CO2 in parts of the basin (Whittaker and others, 2004; Khan and Rostron, 2004; Fisher and others, 2005; Houseworth and others, 2011; Liu and others, 2014). Groundwater-Flow System Recharge to the upper and lower Paleozoic aquifers gener ally happens outside of the Williston Basin on the high eleva tion flanks of structural uplifts to the west and southwest, and immediately adjacent to the southwestern basin margin (figs. 12-14; Downey, 1984a, 1984b; Hannon, 1987; Downey and Dinwiddie, 1988; Busby and others, 1995; Bachu and Hitchon, 1996; Benn and Rostron, 1998; LeFever, 1998; Rostron and Holmden, 2003). Along the flanks of these struc tural uplifts, rocks composing the aquifers were warped upward and exposed (crop out) because of erosion. Infiltration of fresh water on the outcrops in these highland areas from precipita tion (snow and rain) and ephemeral and perennial streamflow losses enters (recharges) the aquifers. Much of this recharge enters local groundwater flow systems, is discharged locally to springs, and seeps along the mountain flanks (Swenson, 1968). Groundwater not discharged from the local flow system eventu ally enters the regional groundwater-flow systems and gener ally flows slowly from the west and southwest toward the east and northeast, ultimately discharging to areas along the eastern and northeastern basin margin in North and South Dakota and parts of Manitoba (figs. 3, 12-14; Swenson, 1968; Downey, 1973; Downey, 1984a, b; Hannon, 1987; Downey and Dinwid die, 1988; Busby and others, 1995; DeMis, 1995; Bachu and Hitchon, 1996; LeFever, 1998; Margitai, 2002).
Groundwater Resources 23 300 MILES 300 KILOMETERS 95° 100° 105° 110° 50° 45° Fargo Casper Pierre Helena Cheyenne Billings Bismarck Rapid City Sioux Falls Grand Forks Great Falls MANITOBA SASKATCHEWAN ONTARIO ALBERTA MINNESOTA NORTH DAKOTA MONTANA IDAHO WYOMING NEBRASKA COLORADO UTAH IOWA Cedar Lake LAKE MANITOBA Lake Winnipegosis Red Ri ver of th e No rt h Fort Peck Lake Lake Sakakawea Lake Oahe Yellowstone Lake SOUTH DAKOTA Mi ss o u r Rive r CANADA UNITED STATES EXPLANATION Base from U.S. Geological Survey digital data, variously dated, various scales Albers Equal-Area Conic projection Standard parallels 29°30' N. and 45°30' N. Central meridian 96°00' W. North American Datum of 1983 Lake Sharpe Lake Francis Case General area of recharge to the Paleozoic aquifers/aquifer systems, including the Pennsylvanian aquifer system, originating as precipitation on outcrops in the highlands General area of discharge as interformational flow to the Lower Cretaceous hydrogeologic units Brine area—Dissolved-solids concentration in groundwater from the Pennsylvanian aquifer system is greater than 100,000 milligrams per liter Approximate limit of the Pennsylvanian and Permian rocks General direction of groundwater flow in the Pennsylvanian aquifer system Northern Great Plains aquifer system boundary (Whitehead, 1996)—Dashed where approximate Williston Basin boundary Y e low s t o ne R iver M iss ou r River LAKE WINNIPEG B A K HI S U P FT Figure 12. General areas of recharge to the Paleozoic aquifers/aquifer systems, and general direction of groundwater flow in, and discharge from, the Pennsylvanian aquifer system in the Williston Basin and adjacent areas, United States and Canada (modified from Downey and Dinwiddie, 1988).
24 Potential Effects of Energy Development, Williston Basin—Water Resources 300 MILES 300 KILOMETERS 95° 100° 105° 110° 50° 45° Fargo Casper Pierre Pierre Helena Cheyenne Billings Bismarck Bismarck Rapid City Sioux Falls Grand Forks Great Falls MANITOBA SASKATCHEWAN ONTARIO ALBERTA MINNESOTA NORTH DAKOTA MONTANA IDAHO WYOMING NEBRASKA COLORADO UTAH IOWA Cedar Lake LAKE MANITOBA Lake Winnipegosis Red Ri ver of th e No rt h Fort Peck Lake Lake Sakakawea Lake Sakakawea Lake Oahe Yellowstone Lake SOUTH DAKOTA
M is so ur R ive r Base from U.S. Geological Survey digital data, variously dated, various scales Albers Equal-Area Conic projection Standard parallels 29°30' N. and 45°30' N. Central meridian 96°00' W. North American Datum of 1983 Lake Sharpe Lake Sharpe EXPLANATION General area of recharge to the Paleozoic aquifers, including the Madison aquifer, originating as precipitation on outcrops in the highlands General area of discharge as interformational flow to the Lower Cretaceous hydrogeologic units General area of discharge as interformational flow to the Cambrian- and Ordovician-age hydrogeologic units Brine area—Dissolved-solids concentration in groundwater from the Madison aquifer is greater than 100,000 milligrams per liter Approximate limit of the Madison Group and stratigraphic equivalents General direction of groundwater flow in the Madison aquifer Northern Great Plains aquifer system boundary (Whitehead, 1996)—Dashed where approximate Williston Basin boundary CANADA UNITED STATES M iss ou r River Y e low s t o ne R iver Y e low s t o ne R iver LAKE WINNIPEG B A K HI S U P FT Figure 13. General areas of recharge to the Paleozoic aquifers/aquifer systems, and general direction of groundwater flow in, and discharge from, the Madison aquifer in the Williston Basin and adjacent areas, United States and Canada (modified from Downey and Dinwiddie, 1988).
Groundwater Resources 25 300 MILES 300 KILOMETERS 95° 100° 105° 110° 50° 45° Fargo Casper Pierre Helena Cheyenne Billings Bismarck Bismarck Rapid City Sioux Falls Grand Forks Great Falls MANITOBA SASKATCHEWAN ONTARIO ALBERTA MINNESOTA NORTH DAKOTA NORTH DAKOTA MONTANA IDAHO WYOMING NEBRASKA COLORADO UTAH IOWA Cedar Lake LAKE MANITOBA Lake Winnipegosis Fort Peck Lake Lake Sakakawea Lake Sakakawea Lake Oahe Y el o ws t o ne R e r Y el o ws t o ne R e r Yellowstone Lake SOUTH DAKOTA Mi ss o u r Rive r EXPLANATION Base from U.S. Geological Survey digital data, variously dated, various scales Albers Equal-Area Conic projection Standard parallels 29°30' N. and 45°30' N. Central meridian 96°00' W. North American Datum of 1983 Lake Sharpe Lake Francis Case General area of recharge to the Paleozoic aquifers/aquifer systems including the Cambrian-Ordovician aquifer system, originating as precipitation on outcrops in the highlands General area of discharge to the land surface General area of recharge as interformational flow from Mississippian-age hydrogeologic units Brine area—Dissolved-solids concentration in groundwater from the Cambrian-Ordovician aquifer system is greater than 100,000 milligrams per liter Approximate limit of the Ordovician rocks Approximate limit of the Cambrian and Ordovician rocks General direction of groundwater flow in the Cambrian-Ordovician aquifer system Northern Great Plains aquifer system boundary (Whitehead, 1996)—Dashed where approximate Williston Basin boundary Red River of the Nort h Mi ss ou r
Ri ve r CANADA UNITED STATES LAKE WINNIPEG B A K HI S U P FT Figure 14. General areas of recharge to the Paleozoic aquifers/aquifer systems, and general direction of groundwater flow in, and discharge from, the Cambrian-Ordovician aquifer system in the Williston Basin and adjacent areas, United States and Canada (modified from Downey and Dinwiddie, 1988).
26 Potential Effects of Energy Development, Williston Basin—Water Resources Estimated rates of regional flow in the Paleozoic aquifers indicate groundwater movement is slow, generally ranging from less than 2 to 10 feet per year (ft/yr) for the Madison aquifer and less than 2 to as much as 75 ft/yr for the Cam brian-Ordovician aquifer (Downey and Dinwiddie, 1988). Dis charge from the Pennsylvanian aquifer system and Madison aquifer flows to adjacent and overlying aquifer systems along eastern subcrops, and much of this discharge is as recharge to the overlying Lower Cretaceous aquifers in eastern North and South Dakota (figs. 3, 12, 13; Swenson, 1968; Downey, 1973, 1984a, b; Downey and Dinwiddie, 1988). Discharge from the Cambrian-Ordovician aquifer system flows to overlying shal low aquifers/aquifer systems or through springs and seeps in North Dakota east of the Williston Basin margin and to overly ing glacial till in northeastern North Dakota and Manitoba (fig. 14; Swenson, 1968; Downey, 1973; Downey and Dinwid die, 1988; Bachu and Hitchon, 1996). In the Williston Basin, upper Paleozoic aquifers and lower Paleozoic aquifers and confining units contain freshwa ter only in the southernmost part of the basin east of the Black Hills uplift in South Dakota (figs. 15, 16) where infiltrat ing meteoric waters recharge the exposed aquifer outcrops. Upper and lower Paleozoic aquifers/confining units contain saline and briny waters throughout the rest of their geographic extent, including the dense brine with dissolved-solids concen trations greater than 100,000 mg/L present in much of eastern Montana and central North Dakota (figs. 3, 15, 16). Dissolvedsolids concentrations increase toward the basin center and with increasing depth, except for local anomalies (Bachu and Hitchon, 1996; Benn and Rostron, 1998). Fresher and lessdense groundwater is hypothesized to flow laterally around and above the margins of the dense brine (dissolved-solids concentrations greater than 100,000 mg/L) present in parts of the upper and lower Paleozoic aquifers/confining units buried in the deepest part of the basin (figs. 3, 15, 16; Downey and others, 1987; Downey and Dinwiddie, 1988; Busby and oth ers, 1995; Bachu and Hitchon, 1996; Benn and Rostron, 1998; LeFever, 1998). Most groundwater flowing laterally around the dense brine discharges to shallower aquifers in eastern North Dakota, whereas groundwater flowing above the dense brine moves upward to the Quaternary unconsolidated glacialand alluvial-deposit aquifers overlying the Northern Great Plains aquifer system and ultimately discharges to springs, streams, and lakes in eastern North Dakota (figs. 12-14). Some of this water reaches the land surface as saline springs or seeps. A small component of the regional groundwaterflow system not diverted around the dense basinal brine is hypothesized to flow east and northeast through the brine at rates much less than the rest of the regional groundwater-flow system (Downey and others, 1987; Downey and Dinwiddie, 1988; Busby and others, 1995; Toop and Tóth, 1995; Bachu and Hitchon, 1996; LeFever, 1998; Jensen and Rostron, 2006). River and Stream Resources The Williston Basin (fig. 1) is within two major river systems—the Missouri River system and the Hudson Bay system. The closed Devils Lake Basin (not shown in fig. 1) in the northeastern Williston Basin in North Dakota does not typically contribute streamflow to a major river system. About 86 percent of the Williston Basin is in the Missouri River sys tem, about 12 percent of the Williston Basin is in the Hudson Bay system, and about 2 percent is in the closed Devils Lake Basin. This section will describe (1) information on existing streamflow data that are available for streams in the Williston Basin, (2) streamflow characteristics for streamgages in the Williston Basin with generally more than 50 years of record, and (3) research and data-collection needs to address informa tion and data gaps. The information on streamflow character istics is presented in sections for major rivers (including the Missouri and Yellowstone Rivers) and large streams. Available Streamflow Data Within the Williston Basin, 360 USGS streamgages have 10 or more years of data collection through water year 2014; a water year is the 12-month period from October 1 through September 30 and is designated by the year in which it ends. The locations and summary information for these streamgages are presented in Appendix figure 1-1 and table 1-1 and summary information also is included in the associated data release (Boughton and others, 2022, table 1-1). For 194 of the 360 streamgages, year-round or seasonal continuous stream flow data have been collected in all, or part of, their data-col lection periods to produce daily streamflow records and annual peak-flow records that represent the maximum instantaneous discharge for each year of a streamgage's operation. Total drainage areas for the 194 streamgages with available con tinuous-record data range from 1.34 to 208,700 square miles (mi2; median=723 mi2). The length of data collection for the 194 streamgages ranges from 10 to 112 years (median=about 25 years). For 166 of the 360 streamgages, data collection has been restricted to crest-stage operations that involve recording the maximum stream stage for each year, making periodic instan taneous discharge measurements, and analyzing the streamstage and discharge data to produce annual peak-flow records. Total drainage areas for the 166 crest-stage streamgages range from 0.06 to 240 mi2 (median=3.0 mi2). The length of data col lection for the 166 crest-stage streamgages ranges from 10 to 56 years (median=19 years).
River and Stream Resources 27 MILES KILOMETERS 96° 100° 104° 108° 112° 116° 48° 46° 44° 42° Fargo Casper Pierre Helena Cheyenne Billings Bismarck Rapid City Sioux Falls Grand Forks Great Falls Base from U.S. Geological Survey digital data, variously dated, various scales Albers Equal-Area Conic projection Standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 NORTH DAKOTA MONTANA WYOMING Fort Peck Lake Lake Sakakawea Lake Oahe Yellowstone Lake SOUTH DAKOTA CANADA UNITED STATES Lake Sharpe Lake Francis Case
Miss o u r Ri ve r Canyon Ferry Lake
Re d Rive r of th e N orth EXPLANATION Dissolved-solids concentration in water from the upper Paleozoic aquifers, in milligrams per liter Aquifers absent NEBRASKA UTAH IDAHO MINNESOTA Missouri River Northern Great Plains aquifer system boundary (Whitehead, 1996)—Dashed where approximate Williston Basin boundary
Y e o w s t o n e
Riv er 0 to 1,000 Greater than 1,000 to 3,000 Greater than 3,000 to 10,000 Greater than 10,000 to 100,000 Greater than 100,000 to 300,000 Greater than 300,000 B A K HI S U P FT Figure 15. Dissolved-solids concentrations in water from upper Paleozoic aquifers in the Williston Basin and adjacent areas (modified from Whitehead, 1996).
28 Potential Effects of Energy Development, Williston Basin—Water Resources 96° 100° 104° 108° 112° 116° 48° 46° 44° 42° Fargo Casper Pierre Helena Cheyenne Billings Bismarck Rapid City Sioux Falls Grand Forks Great Falls NORTH DAKOTA MONTANA WYOMING Fort Peck Lake Lake Sakakawea Lake Oahe Yellowstone Lake SOUTH DAKOTA CANADA UNITED STATES Lake Sharpe Lake Francis Case
Miss o u r Ri ve r Canyon Ferry Lake
Re d Rive r of th e N orth EXPLANATION Dissolved-solids concentration in water from the lower Paleozoic aquifers, in milligrams per liter 0 to 1,000 Greater than 1,000 to 3,000 Greater than 3,000 to 10,000 Greater than 10,000 to 100,000 Greater than 100,000 to 300,000 Greater than 300,000 Aquifers absent NEBRASKA UTAH IDAHO MINNESOTA Missouri River Northern Great Plains aquifer system boundary (Whitehead, 1996)—Dashed where approximate Williston Basin boundary
Y e o w s t o n e
Riv er MILES KILOMETERS Base from U.S. Geological Survey digital data, variously dated, various scales Albers Equal-Area Conic projection Standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 B A K HI S U P FT Figure 16. Dissolved-solids concentrations in water from the lower Paleozoic aquifers and confining units in the Williston Basin and adjacent areas (modified from Whitehead, 1996).
River and Stream Resources 29 Streamflow Characteristics To describe streamflow characteristics within the Wil liston Basin, 17 streamgages (table 3) were selected primarily because of record length and representation of large areas (fig. 17). The selected streamgages generally had greater than 50 years of data collection each within a 61-year base period of water years 1954 through 2014 or represented a large area of the Williston Basin. The start of the base period was defined primarily by the closure of Garrison Dam (fig. 17) on the Mis souri River (forming Lake Sakakawea), and the subsequent large-scale coordination of reservoir operations on the Mis souri River (U.S. Army Corps of Engineers [USACE], 2006). Within the 1954 through 2014 base period, all the selected streamgages have consistent hydrologic regimes with respect to regulation; that is, for streamgages affected by major reser voirs, the major reservoirs were in place before 1954. The selected streamgages were classified as representing either major rivers or large streams (table 3). Major rivers (that is, the Missouri and Yellowstone Rivers with total drainage areas greater than 50,000 mi2) flow into and through the Wil liston Basin but have substantial parts of their drainage basins upstream from the Williston Basin. In contrast, the large streams have total drainage areas that range from about 551 to 22,452 mi2, and generally all or most of their drainage basins are within the Williston Basin (contributing drainage basin area). The large streams were further classified by ecoregion (U.S. Environmental Protection Agency [EPA], 2013b): (1) the Northwestern Glaciated Plains ecoregion, (2) the Northern Glaciated Plains ecoregion, or (3) the Northwestern Great Plains ecoregion. The streamflow characteristics presented represent data analysis completed on different temporal scales. Monthly and annual streamflow characteristics facilitate discussion of seasonal and interannual variability in streamflow and provide general information on primary drivers of streamflow, and reliability of streamflow on seasonal and multiple-year scales. Daily streamflow and annual extreme flow characteristics provide information on critical short-term (weekly, daily, or instantaneous) and extreme streamflow conditions, such as floods or zero-streamflow conditions. Daily streamflow and annual extreme flow characteristics provide hydrologic information that might be relevant to infrastructure design and evaluating potential causes and environmental effects of accidental spills of product, leakages of water extracted from oil and coal-bed methane wells, or the intentional illegal dis charges of the extracted waters. Streamflow Data Compilation and Analysis Daily mean streamflow and annual peak-flow data for the selected streamgages were retrieved from the USGS National Water Information System (NWIS; USGS, 2015c) database. Data retrievals were restricted to complete water years within the 1954 through 2014 base period. Monthly and annual mean streamflows were computed from the daily mean streamflows using the USGS Automated Data and Processing System (USGS, 2003) and summary statistics of the monthly and annual mean streamflows are presented in a data release (Boughton and others, 2022, table 1-2). Some streamgages did not have complete streamflow records for all of the 61 years in the 1954-2014 base period; for those streamgages, the sum mary statistics of the monthly and annual mean streamflows were computed for the periods of record indicated in table 1-2 (Boughton and others, 2022). Duration hydrograph data were computed using the USGS Surface-Water Statistics program (SWSTAT; USGS, 2015b). Duration hydrograph data are presented for the none ceedance 10th-, 25th-, 50th- (median), 75th-, and 90th percen tiles for each day of the water year (figs. 18-20). The 10thpercentile duration streamflow value for a given day indicates a low-streamflow condition such that streamflows are less than or equal to the value for the given day only 10 percent of the time. Conversely, the 90th-percentile duration streamflow value for a given day indicates a high-streamflow condition such that streamflows are less than or equal to the value for the given day 90 percent of the time. Annual 7-day low-flow data were computed using the USGS SWSTAT (USGS, 2015b). The annual 7-day low flow is the lowest mean streamflow for any 7 consecutive days in a given year. The annual 7-day low flow was computed accord ing to the standard climatic year of April 1 through March 31. The magnitude of the variability in streamflow character istics among the selected streamgages introduces challenges in presenting the information. In figures 18-20, log-scale plots are used with the intent of showing the large relative variability in characteristics among the selected streamgages while also maintaining some resolution in the characteristics of individual streamgages. The log-scale presentation does not allow accurate presentation of low values near zero. Thus, in figures 19-20 the y-axis minimum is set to 1 ft3/s; in those figures, actual streamflow values less than 1 ft3/s were plotted at 1 ft3/s, which is considered a reasonable representation of at or near-zero streamflows.
30 Potential Effects of Energy Development, Williston Basin—Water Resources Table 3. Information on selected streamgages on major rivers and large streams in or near the Williston Basin, 1954 through 2014. [Water year is the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends. --, not available, NAVD 88, North American Vertical Datum of 1988] Streamgage number or geographic area Streamgage name Stream classification (and ecoregion, if applicable) Latitude, in decimal degrees Longitude, in decimal degrees Drainage area, in square miles Total Contributing Sheyenne River near Warwick, North Dakota Large stream (Northern Glaciated Plains) −98.7162 2,070 Souris River near Westhope, North Dakota Large stream (Northern Glaciated Plains) −100.9585 16,900 6,600 Missouri River below Fort Peck Dam, Montana Major river −106.3563 56,490 56,490 Milk River at Nashua, Montana Large stream (Northwestern Glaciated Plains) −106.3643 22,452 20,254 Redwater River at Circle, Montana Large stream (Northwestern Great Plains) −105.5756 Poplar River near Poplar, Montana Large stream (Northwestern Glaciated Plains) −105.1786 3,140 3,140 Missouri River near Culbertson, Montana Major river −104.4733 89,959 89,858 Yellowstone River at Miles City, Montana Major river −105.8600 48,288 47,596 Yellowstone River near Sidney, Montana Major river −104.1554 69,099 68,407 Missouri River near Williston, North Dakota Major river −103.7146 164,500 164,500 Little Missouri River near Watford City, North Dakota Large stream (Northwestern Great Plains) −103.2519 8,310 8,310 Knife River at Hazen, North Dakota Large stream (Northwestern Great Plains) −101.6221 2,240 2,240 Missouri River at Bismarck, North Dakota Major river −100.8214 186,400 186,400 Heart River near Mandan, North Dakota Large stream (Northwestern Great Plains) −100.9746 3,310 3,310 Cannonball River at Breien, North Dakota Large stream (Northwestern Great Plains) −100.9344 4,100 4,100 Grand River at Little Eagle, South Dakota Large stream (Northwestern Great Plains) −100.8182 5,316 5,316 Moreau River near Whitehorse, South Dakota Large stream (Northwestern Great Plains) −100.8429 4,889 4,872 Williston Basin area
River and Stream Resources 31 Table 3. Information on selected streamgages on major rivers and large streams in or near the Williston Basin, 1954 through 2014.—Continued [Water year is the 12-month period from October 1 through September 30, and is designated by the calendar year in which it ends. --, not available, NAVD 88, North American Vertical Datum of 1988] Streamgage number or geographic area Streamgage name Mean elevation, in feet above NAVD 88 Mean annual precipitation, in inches Mean annual air temperature, in degrees Fahrenheit Percentage of drainage area or study area covered by lakes and wetlands1 Drainage basin/water yield, in percent2 Period of analysis, in water years Number of water years in period of analysis Sheyenne River near Warwick, North Dakota 1,628 Sheyenne River/9.8 1954-2014 Souris River near Westhope, North Dakota 1,840 Souris River/5.0 1954-2014 Missouri River below Fort Peck Dam, Montana 4,654 Missouri River, Fort Peck/12.6 1954-2000, 2002-14 Milk River at Nashua, Montana 3,007 Milk River/3.0 1954-2014 Redwater River at Circle, Montana 2,809 Redwater River/1.7 1954-71, 1975-2004, 2010-13 Poplar River near Poplar, Montana 2,700 Poplar River/3.5 1954-69, 1976-79, 1982-2014 Missouri River near Culbertson, Montana 3,974 Missouri River, Culbert/9.7 1959-2014 Yellowstone River at Miles City, Montana 5,490 Yellowstone River, Miles City/18.3 1954-2014 Yellowstone River near Sidney, Montana 4,994 Yellowstone River, Sidney/14.0 1954-2014 Missouri River near Williston, North Dakota Missouri River, Williston/-- 1954-1964 Little Missouri River near Watford City, North Dakota 3,101 Little Missouri River/5.5 1954-2014 Knife River at Hazen, North Dakota 2,190 Knife River/5.9 1954-2014 Missouri River at Bismarck, North Dakota 2,211 Missouri River, Bismarck/-- 1954-2014 Heart River near Mandan, North Dakota 2,340 Heart River/6.5 1954-2014 Cannonball River at Breien, North Dakota 2,420 Cannonball River/5.0 1954-2014 Grand River at Little Eagle, South Dakota 2,582 Grand River/4.0 1954-2014 Moreau River near Whitehorse, South Dakota 2,623 Moreau River/4.7 1954-2014 Williston Basin area Williston Basin/-- 1Percentage of area covered by lakes and wetlands was determined by geographic information system (GIS) analysis of the National Wetlands Inventory dataset (U.S. Fish and Wildlife Service, 2014). For an individual streamgage, the analysis was restricted to the part of the drainage area within the Williston Basin area boundary. Although the analysis does not include the entire drainage areas of the streamgages, reasonable representation of relative differences in depressional storage among streamgages is provided. 2The drainage basin water yield is defined as the ratio (expressed in percentage) of the mean annual runoff in inches (from Boughton and others, 2022, table 1-2) relative to the mean annual precipitation in inches (from previous column in this table).
32 Potential Effects of Energy Development, Williston Basin—Water Resources OAHE DAM # # ## # # # # # # # # # # # # #
Y ello w s t one
R ver S o u r s
R e r Missouri River Mi ss ou ri
R e r Sheyenne River Grand River Moreau River Poplar R Cannonball River Milk River Fort Peck Lake Lake Sakakawea Lake Oahe R ed w at er R Knife River Heart River Powder River Missouri River Little Musselshell River Bighorn River 100° 105° 110° 48° 45° MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA Base map modified from U.S. Geological Survey, Esri, and Commission for Environmental Cooperation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 EXPLANATION UNITED STATES CANADA MILES KILOMETERS Williston Basin boundary Bakken Formation boundary U.S. Geological Survey streamgage and identifier Northern Glaciated Plains Northwestern Glaciated Plains Northwestern Great Plains U.S. Environmental Protection Agency level III ecoregion (U.S. Environmental Protection Agency, 2013b) GARRISON DAM FORT PECK DAM Figure 17. Locations of selected streamgages on major rivers and large streams in or near the Williston Basin.
River and Stream Resources 33 A. Missouri River below Fort Peck Dam, Montana Streamgage 06132000 B. Missouri River near Culbertson, Montana Streamgage 06185500 C. Yellowstone River at Miles City, Montana Streamgage 06309000 Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. 1,000 10,000 100,000 1,000,000 1,000 10,000 100,000 1,000,000 Streamflow, in cubic feet per second D. Yellowstone River near Sidney, Montana Streamgage 06329500 E. Missouri River near Williston, North Dakota Streamgage 06330000 1,000 10,000 100,000 1,000,000 F. Missouri River at Bismarck, North Dakota Streamgage 06342500 Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Month Month EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Duration hydrograph streamflow Annual extreme flows 75th-percentile nonexceedance 90th-percentile nonexceedance Median 25th-percentile nonexceedance 10th-percentile nonexceedance Annual peak flow (all annual peak flows for the period of analysis are presented, plotted at the calendar day of occurrence) Annual 7-day low flow (all annual 7-day low flows for the period of analysis are presented, plotted at the calendar day of occurrence). Actual streamflow values less than 1 cubic foot per second are plotted at 1 cubic foot per second Figure 18. Duration hydrograph streamflow statistics and annual extreme flows for selected streamgages on major rivers in the Williston Basin, Montana, North Dakota, and South Dakota.
34 Potential Effects of Energy Development, Williston Basin—Water Resources EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Duration hydrograph streamflow Annual extreme flows 75th-percentile nonexceedance 90th-percentile nonexceedance Median 25th-percentile nonexceedance 10th-percentile nonexceedance Annual peak flow (all annual peak flows for the period of analysis are presented, plotted at the calendar day of occurrence) Annual 7-day low flow (all annual 7-day low flows for the period of analysis are presented, plotted at the calendar day of occurrence). Actual streamflow values less than 1 cubic foot per second are plotted at 1 cubic foot per second Month Month Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Streamgage 05056000 Streamgage 05124000 Streamgage 06174500 Streamgage 06181000 Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. 1,000 10,000 100,000 Streamflow, in cubic feet per second 1,000 10,000 100,000 A. Sheyenne River near Warwick, North Dakota B. Souris River near Westhope, North Dakota C. Milk River at Nashua, Montana D. Poplar River near Poplar, Montana Figure 19. Duration hydrograph streamflows and annual extreme flows for selected streamgages on large streams in the Northern and Northwestern Glaciated Plains ecoregions.
River and Stream Resources 35 Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Duration hydrograph streamflow Annual extreme flows Annual peak flow (all annual peak flows for the period of analysis are presented, plotted at the calendar day of occurrence) 75th-percentile nonexceedance 90th-percentile nonexceedance Median 25th-percentile nonexceedance 10th-percentile nonexceedance Annual 7-day low flow (all annual 7-day low flows for the period of analysis are presented, plotted at the calendar day of occurrence). Actual streamflow values less than 1 cubic foot per second are plotted at 1 cubic foot per second A. Redwater River at Circle, Montana B. Little Missouri River near Watford City, North Dakota C. Knife River at Hazen, North Dakota D. Heart River near Mandan, North Dakota E. Cannonball River at Breien, North Dakota F. Grand River at Little Eagle, South Dakota G. Moreau River near Whitehorse, South Dakota 1,000 10,000 100,000 1,000 10,000 100,000 Streamflow, in cubic feet per second 1,000 10,000 100,000 1,000 10,000 100,000 Streamgage 06177500 Streamgage 06337000 Streamgage 06340500 Streamgage 06349000 Streamgage 06354000 Streamgage 06357800 Streamgage 06360500 Month Month Figure 20. Duration hydrograph streamflows and annual extreme flows for selected streamgages on large streams in the Northwestern Great Plains ecoregion.
36 Potential Effects of Energy Development, Williston Basin—Water Resources In addition to the graphical presentation of streamflow characteristics in figures 18-20, summary statistics were computed for the streamflow characteristics of monthly and annual mean streamflows, and annual extreme flows (that is, the annual peak flow and the annual 7-day low flow) and have been presented in tabular form in a data release (Boughton and others, 2022, tables 1-2 and 1-3). The summary statistics include the minimum, 10th-percentile, 25th-percentile, 50thpercentile (median), mean, 75th-percentile, 90th-percentile, and maximum values. The percentile values represent none ceedance percentiles and, for each streamflow characteristic, were determined by ranking the data from lowest to highest and dividing the rank by the total number of observations; thus, the percentiles represent the frequency of occurrence within the years of the analysis period, with no adjustment to represent probability of occurrence within longer periods. For the annual extreme flows (that is, the annual peak flow and the annual 7-day low flow), frequency analyses often are done to estimate probabilities within longer periods for purposes, including structure design or regulation of wastewater dis charges; however, such frequency analyses are appropriately done on a station-by-station basis using all available data. The use of the common base period of 1954 through 2014 in this study results in truncated datasets for some streamgages that would not be appropriate for frequency analysis. Hydrographic information presented (including drain age area, stream length, mean elevation, and in some cases percentage of basin greater than 6,000 ft in elevation) was determined by geographic information system (GIS) analysis of medium resolution (1:100,000 scale and 30 meter) digital datasets. The digital datasets include the National Elevation Dataset (Gesch and others, 2002), National Hydrography Dataset (NHD; USGS, 2015a), and National Hydrography Dataset Plus Version 2 (NHDPlus; Horizon Systems Corpo ration, 2013); however, drainage areas for streamgages that are reported in tables were obtained from the NWIS database (USGS, 2015c) and were determined using various meth ods. Climatic basin characteristics information (including mean annual precipitation and mean annual air temperature) was determined by GIS analysis of the Parameter-elevation Regression on Independent Slopes Model (PRISM; PRISM Climate Group, 2004) and the Long Term mean Climate Grids for Canada (Natural Resources Canada, 2015). Information on density of depressional storage, or percentage of drainage area covered by lakes and wetlands, was determined by GIS analysis of the National Wetlands Inventory (NWI) dataset (U.S. Fish and Wildlife Service [USFWS], 2014). Several drainage basin characteristics of the 17 selected streamgages are presented in table 3. Also included in table 3 is the drainage basin water yield, which provides an index of the efficiency in translating the deposited atmospheric precipi tation into streamflow past a streamgage. The drainage basin yield is defined as the ratio (expressed in percentage) of the mean annual runoff in inches (Boughton and others, 2022, table 1-2) relative to the mean annual precipitation in inches (table 3). Major Rivers The Missouri and Yellowstone Rivers are considered major rivers that flow into and through the Williston Basin (fig. 17). These major rivers have substantial parts of their drainage basins that are outside the Williston Basin, but they also have long segments of their channels within the area. Description of Major River Hydrography Missouri River enters the upper reaches of Fort Peck Lake west of the Williston Basin (fig. 17), at which point the drainage area is about 41,000 mi2. A substantial part of the Missouri River Basin upstream from the Williston Basin (hereinafter referred to as the "upstream Missouri River Basin") is mountainous; about 31 percent of the drainage area is higher than 6,000 ft in elevation. Much of the streamflow generated in the upstream Missouri River Basin results from high-elevation snowmelt that typically happens in May and June (Pederson and others, 2010); however, the upstream Missouri River Basin is somewhat strongly regulated because four major reservoirs have multipurpose operations that include flood control. The four reservoirs individually have total storage capacities that exceed 325,000 acre-feet (acre-ft) and cumulatively have about 4,300,000 acre-ft of total storage capacity (Sando and others, 2016). Within the Williston Basin, Fort Peck Lake extends about 110 miles (mi) from the western boundary of the Williston Basin to Fort Peck Dam (fig. 17). Fort Peck Lake has a storage capacity of 18,463,000 acre-ft, and maximum depth at full pool of about 220 ft (USACE, 2015a). The largest tributary to Fort Peck Lake is the Musselshell River, which has a drainage area of about 8,000 mi2. From Fort Peck Dam, the Missouri River flows for about 185 mi to the confluence with the Yel lowstone River. The largest tributaries in this reach are the Milk River and the Poplar River (fig. 17). Upstream from the confluence with the Yellowstone River, the Missouri River has a drainage area of about 90,000 mi2, and about 15 percent of the drainage area is higher than 6,000 ft in elevation. As it enters the western boundary of the Williston Basin (fig. 17), the Yellowstone River has a drainage area of about 48,000 mi2, and about 33 percent of the basin is higher than 6,000 ft in elevation. Similar to the upstream Missouri River Basin, much of the streamflow generated in the upstream Yel lowstone River Basin results from high-elevation snowmelt that typically happens in May and June (Pederson and others, 2010); however, the upstream Yellowstone River Basin (with a single major reservoir with multipurpose operations that include flood control) has substantially less major regula tion than the upstream Missouri River Basin because just one primary reservoir is in operation on the river. Bighorn Lake, formed by Yellowtail Dam (not shown in fig. 1), is on the Bighorn River far upstream from the Williston Basin and has a total storage capacity of about 1,400,000 acre-ft (Bureau of Reclamation, 2015b). Within the Williston Basin, the Yel lowstone River flows from the western boundary for about
River and Stream Resources 37 170 mi to the confluence with the Missouri River (fig. 17). The largest tributary to the Yellowstone is the Powder River with a drainage area of about 13,400 mi2, most of which is outside of the Williston Basin. The Intake Diversion Dam and canal (not shown in fig. 1), on the Yellowstone River about 70 mi upstream from the confluence with the Missouri River, diverts streamflow from the Yellowstone River to the Lower Yel lowstone Project (Bureau of Reclamation, 2015a). The Intake Diversion Dam canal has a capacity of about 1,200 ft3/s and on a mean annual basis diverts about 327,046 acre-ft, or about 450 ft3/s of streamflow (Bureau of Reclamation, 2015a). At its confluence with the Missouri River, the Yellowstone River has a drainage area of about 69,000 mi2, and about 25 percent of the drainage area is higher than 6,000 ft in elevation. From the confluence with the Yellowstone River, the Mis souri River flows about 15 to 35 mi (depending on the storage in Lake Sakakawea) to the upper reaches of Lake Sakakawea formed by Garrison Dam (fig. 17). At full pool, Lake Saka kawea extends for about 175 mi, has a storage capacity of 23,821,000 acre-ft, and has a maximum depth of about 180 ft (USACE, 2015b). The largest tributary to Lake Sakakawea is the Little Missouri River (fig. 17). From Garrison Dam, the Missouri River flows about 80 to 130 mi (depending on the storage in Lake Oahe) to the upper reaches of Lake Oahe, which is formed by Oahe Dam (fig. 17). The largest tribu taries in the reach are the Knife River and the Heart River (fig. 17). At full pool, Lake Oahe has a storage capacity of 23,137,000 acre-ft, and a maximum depth of about 205 ft (USACE, 2015c). The distance from the upper reaches of Lake Oahe to Oahe Dam at full pool is about 230 mi; however, the main body of Lake Oahe exits the Williston Basin about 95 mi downstream from the upper reaches. The largest tributaries to Lake Oahe in the Williston Basin are the Cannonball, Grand, Moreau, and Sheyenne Rivers (fig. 17). Description of Major River Streamflow Characteristics Duration hydrographs of daily streamflows are presented in conjunction with annual extreme flows (that is, annual peakflow and annual 7-day low-flow data) for the six streamgages (06132000, 06185500, 06309000, 06329500, 06330000, and 06342500; fig. 18) on the major rivers (fig. 17). The summary statistics of monthly and annual mean streamflows and sum mary statistics of annual extreme flows for these streamgages described below are presented as a data release (Boughton and others, 2022, tables 1-2 and 1-3, respectively). Streamflows for the Missouri River below Fort Peck Dam, Montana (streamgage 06132000; contributing drain age area of 56,490 mi2; table 3; figs. 17, 18A), represent the releases from Fort Peck Lake that are controlled by complex reservoir operations described in USACE (2006). The large effects of regulation are evidenced by generally small seasonal and interannual variability in streamflows. Median monthly releases range from 6,710 ft3/s in April to 11,000 ft3/s in Feb ruary, and median annual runoff is 2.14 inches (in.) (Boughton and others, 2022, table 1-2). Annual peak flows range from 3,900 to 65,900 ft3/s (median=14,400 ft3/s) (Boughton and others, 2022, table 1-3), and are in many months, but most often are in January and February (fig. 18A). Annual 7-day low flows range from 1,390 to 7,860 ft3/s (median=4,410 ft3/s) (Boughton and others, 2022, table 1-3) and most often are in October through November and March through April (fig. 18A). Streamflows for Missouri River near Culbertson, Mont. (streamgage 06185500; contributing drainage area of 89,858 mi2; table 3; figs. 17, 18B), also are strongly affected by regulation from Fort Peck Dam (fig. 17). Median monthly streamflows range from 7,470 ft3/s in October to 11,600 ft3/s in February, and median annual runoff is 1.45 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 8,620 to 104,000 ft3/s (median=16,700 ft3/s) (Boughton and others, 2022, table 1-3), and are in many months, but most often are in March and April (fig. 18B). Differences in the timing of annual peak flows between streamgages 06132000 and 06185500 primarily reflect tributary inflows from the Milk and Poplar Rivers in March and April. Annual 7-day low flows range from 2,130 to 9,590 ft3/s (median=5,580 ft3/s) (Boughton and others, 2022, table 1-3), and most often are in March through May and during October through Decem ber (fig. 18B). The streamflow characteristics for streamgage 06185500 represent strong effects of regulation by Fort Peck Dam with generally small effects from tributary inflows. Median annual streamflow of the Missouri River increases by about 6 percent from 8,910 ft3/s at streamgage 06132000 to 9,450 ft3/s at streamgage 06185500 (fig. 17) (Boughton and others, 2022, table 1-2), associated with an increase in drainage area of about 59 percent. Most of the Missouri River streamflow is generated upstream from the Williston Basin, and streamflow inputs generally are small in the reach from below Fort Peck Dam to the confluence with the Yellowstone River. The Yellowstone River at Miles City, Mont. (streamgage 06309000; contributing drainage area of 47,596 mi2; table 3; figs. 17, 18C), is about 15 mi upstream from the western boundary of the Williston Basin and largely is unaffected by regulation structures. Streamflows for streamgage 06309000 reflect a high-elevation-snowmelt dominated hydrologic regime within a large predominantly unregulated drain age basin. The snowmelt-dominated hydrologic regime is evidenced by somewhat large seasonal variability in streamflows but generally small interannual (year-to-year) variability in streamflows. Median monthly streamflows range from 5,760 ft3/s in January to 29,700 ft3/s in June, and median annual runoff is 3.37 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 24,100 to 102,000 ft3/s (median=48,100 ft3/s) (Boughton and others, 2022, table 1-3). About 95 percent of annual peak flows have been in mid-May through early July (fig. 18C), but about 28 percent of annual peak stages have been in late-February or March (USGS, 2015c), presumably associated with the start of low-elevation snow and ice melt, the transition from ice cover to open-channel streamflow, and the formation of
38 Potential Effects of Energy Development, Williston Basin—Water Resources ice jams that can impound streamflow and increase the river stage. Annual 7-day low flows range from 1,830 to 7,450 ft3/s (median=3,460 ft3/s) (Boughton and others, 2022, table 1-3) and happen most frequently in December through February (fig. 18C). The Yellowstone River near Sidney, Mont. (streamgage 06329500; contributing drainage area of 68,407 mi2; table 3; figs. 17, 18D), is about 155 mi downstream from streamgage 0630900 and about 30 mi upstream from the confluence with the Missouri River. Streamflow for streamgage 06329500 reflects a high-elevation-snowmelt dominated hydrologic regime within a large predominantly unregulated drainage basin. Median monthly streamflow ranges from 6,160 ft3/s in January to 32,600 ft3/s in June, and median annual runoff is 2.40 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 23,000 to 124,000 ft3/s (median=54,300 ft3/s) (Boughton and others, 2022, table 1-3). About 95 percent of annual peak flows have been in mid-May through early July (fig. 18D); however, about 25 percent of annual peak stages have been in late-February or March (USGS, 2015c), presumably associated with the start of low-elevation snow and ice melt, the transition from ice cover to open-channel streamflow, and the formation of ice jams that can impound streamflow and increase the river stage. Annual 7-day low flows range from 1,010 to 7,140 ft3/s (median=3,180 ft3/s) Boughton and others, 2022, table 1-3), and most often are in December and January (fig. 18D). Median annual streamflow of the Yellowstone River only increases by about 2.5 percent from 11,800 ft3/s at streamgage 06309000 to 12,100 ft3/s at streamgage 06329500 (Boughton and others, 2022, table 1-2), associated with an increase in drainage area of about 43 per cent. The small increase in median annual streamflow between streamgages 06309000 and 06329500 is partly affected by a diversion canal about 40 mi upstream from streamgage 06329500, which on a mean annual basis diverts about 450 ft3/s. But clearly most of the Yellowstone River stream flow is generated upstream from the Williston Basin, and streamflow inputs generally are small within the Williston Basin. The Missouri River near Williston, North Dakota (streamgage 06330000; contributing drainage area of 164,500 mi2; table 3; figs. 17, 18E), is about 30 mi down stream from the confluence of the Missouri and Yellowstone Rivers. The period of analysis for streamgage 06330000 is short (1954-64; 11 years; table 3) within the period of coordinated operations of Fort Peck and Garrison Dams. Data for streamgage 06330000 are presented to provide a general qualitative description of the somewhat short but complex reach where the strongly regulated streamflow inputs of the Missouri River interact with the predominantly unregulated inputs of the Yellowstone River. Median monthly streamflow ranges from 11,700 ft3/s in January to 41,500 ft3/s in June, and median annual runoff is 1.63 in (Boughton and others, 2022, table 1-2). For streamgage 06330000, the highest and lowest streamflow months (June and January, respectively) are consistent with the highest and lowest streamflow months for the predominantly unregulated Yellowstone River near streamgage 06329500 (fig. 17). Annual peak flows range from 38,100 to 170,000 ft3/s (median=73,400 ft3/s) (Boughton and others, 2022, table 1-3). About 65 percent of annual peak flows have been in May and June (fig. 18E), and about 35 per cent of annual peak flows have been in March and early April. In about 45 percent of years, annual peak stage has happened in late March and early April (USGS, 2015c), presumably associated with the start of low-elevation snow and ice melt and the transition from ice cover to open-channel stream flow. Annual 7-day low flows range from 6,640 to 9,190 ft3/s (median=8,260 ft3/s) (Boughton and others, 2022, table 1-3), and most often are in November through January (fig. 18E). The Missouri River at Bismarck, N. Dak. (streamgage 06342500; contributing drainage area of 186,400 mi2; table 3; figs. 17, 18F), is about 75 mi downstream from Garrison Dam. Streamflows for streamgage 06342500 are strongly regulated by complex reservoir operations of Lake Saka kawea described in USACE (2006). Median monthly stream flow ranges from 16,600 ft3/s in October to 24,500 ft3/s in February, and median annual runoff is 1.57 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 17,100 to 155,000 ft3/s (median=33,600 ft3/s) (Boughton and others, 2022, table 1-3). Annual peak flows can happen in any month but most frequently have been in January through July (fig. 18F). Annual 7-day low flows range from 4,860 to 20,400 ft3/s (median=11,200 ft3/s) (Boughton and others, 2022, table 1-3), and most often have been in March through June and October through November (fig. 18F). Large Streams In general, streamflow characteristics of streams origi nating in or near the Williston Basin are driven by complex interactions between climatic, geologic, topographic, and land-cover and use characteristics; and interactions of ground water and surface water. Anthropogenic activities, including reservoir and irrigation operations, also contribute to stream flow variability. Streams in the Williston Basin generally have large seasonal and interannual variability in streamflows. Large-scale spatial differences in streamflow characteristics are substantially affected by spatial variability in precipitation, air temperature, and drainage characteristics (especially the density of depressional storage or percentage of area covered by lakes and wetlands). Variability in snowpack accumulation in relation to the frequency and intensity of spring and sum mer rainfall contributes to differences in seasonal streamflow characteristics among streams. Throughout the Williston Basin, mean monthly air tem peratures consistently are below freezing in December through February (PRISM Climate Group, 2004), when precipitation most often is accumulating snowfall. Throughout most of the Williston Basin, in March and April, mean monthly air tem peratures generally increase to near or above freezing, which causes snowmelt runoff with associated varying amounts of streamflow. Snowmelt runoff and streamflows can be
River and Stream Resources 39 enhanced by frozen-soil conditions (Dunne and Black, 1971; Shanley and Chalmers, 1999) and ice-jam releases (White and Zufelt, 1994). The highest precipitation months are May through July (PRISM Climate Group, 2004; Mock, 1996), and mean precipitation for these months accounts for about 55 percent of mean annual precipitation. In May through July, precipitation most often is rainfall, and streamflow variably responds to the spring and summer rainfall. Large Streams in the Northern and Northwestern Glaciated Plains Ecoregions The northern and eastern parts of the Williston Basin are in the Northern Glaciated Plains and Northwestern Glaci ated Plains ecoregions (Bryce and others, 1996; Woods and others, 2002). In or near the Williston Basin, four long-term streamgages are on large streams in the Northern and North western Glaciated Plains ecoregions: (1) Sheyenne River near Warwick, N. Dak. (streamgage 05056000); (2) Souris River near Westhope, N. Dak. (streamgage 05124000); (3) Milk River at Nashua, Mont. (streamgage 06174500); and (4) Poplar River near Poplar, Mont. (streamgage 06181000) (fig. 17; table 3). Duration hydrographs of daily streamflows are presented in con junction with annual extreme flows (that is, annual peak-flow and annual 7-day low flow data) for the four streamgages on large streams in the Northern and Northwestern Glaciated Plains ecoregions (fig. 19). The Sheyenne River originates within the Williston Basin and flows about 190 mi from its headwaters to the eastern boundary of the Williston Basin (fig. 17). The Sheyenne River is not regulated by major reservoirs within the Williston Basin. The Sheyenne River near Warwick, N. Dak. (streamgage 05056000; fig. 17; contributing drainage area of 760 mi2; table 3; fig. 19A), is about 5 mi downstream from the eastern boundary of the Williston Basin. In relation to the entire Wil liston Basin and the other large streams, the Sheyenne River drainage basin has high mean annual precipitation (17.5 in.), low mean annual air temperature (39.7 degrees Fahrenheit [°F]), and a high percentage of lakes and wetlands (9.6 percent; table 3); these characteristics interact with other drainage basin characteristics and contribute to high drainage basin water yield (9.8 percent; table 3). Median monthly streamflows range from 5.2 ft3/s in January to 199 ft3/s in April, and median annual run off is 1.20 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 66 to 8,200 ft3/s (median=1,090 ft3/s) (Boughton and others, 2022, table 1-3). About 75 percent of annual peak flows have been in March and April (fig. 19A) asso ciated with the typical snowmelt runoff period. Annual 7-day low flows range from 0 to 41 ft3/s (median=2.0 ft3/s) Boughton and others, 2022, table 1-3), and most often are in February through March and in late July through September (fig. 19A). At or near-zero streamflows are more likely in the summer than in the winter. The Souris River originates in the Williston Basin in Saskatchewan, Canada, flows through part of North Dakota, and then flows into Manitoba, Canada (fig. 17). Several reservoirs in Saskatchewan and North Dakota regulate streamflows of the Souris River. The Souris River near Westhope, N. Dak. (streamgage 05124000; contributing drainage area of 6,600 mi2; table 3; fig. 19B), is near where the Souris River exits the Williston Basin (fig. 17). In relation to the entire Williston Basin and the other large streams, the Souris River drainage basin has high mean annual precipitation (17.1 in.), low mean annual air temperature (37.8 °F), and a high per centage of lakes and wetlands (8.4 percent; table 3); these characteristics interact with other drainage basin character istics and contribute to moderate drainage basin water yield (5.0 percent; table 3). Median monthly streamflows range from 23 ft3/s in January and February to 474 ft3/s in May, and median annual runoff is 0.40 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 30 to 30,400 ft3/s (median=1,100 ft3/s) (Boughton and others, 2022, table 1-3). About 60 percent of annual peak flows have been in April and May (fig. 19B) associated with the typical snowmelt runoff period. Annual 7-day low flows range from 0 to 245 ft3/s (median=1.5 ft3/s) (Boughton and others, 2022, table 1-3). Annual 7-day low flows most often are in November through April (fig. 19B). At or near-zero streamflows are somewhat likely in the winter. The Milk River originates in northwestern Montana, then flows northeast into Alberta, Canada, then eventually re-enters Montana and flows for about 90 mi to where it enters the western boundary of the Williston Basin, and then flows for about 430 mi through the Williston Basin to its confluence with the Missouri River (fig. 17). The Milk River is exten sively regulated, primarily for large-scale irrigation operations. The Milk River at Nashua, Mont. (streamgage 06174500; contributing drainage area of 20,254 mi2; table 3; fig. 19C), is about 23 mi upstream from the confluence with the Mis souri River (fig. 17). In relation to the entire Williston Basin and the other large streams, the Milk River drainage basin has low mean annual precipitation (13.5 in.), moderate air mean annual temperature (40.5 °F), and moderate percentage of lakes and wetlands (2.5 percent; table 3); these characteristics interact with other drainage basin characteristics and contrib ute to low drainage basin water yield (3.0 percent; table 3). Median monthly streamflows range from 130 ft3/s in Janu ary to 700 ft3/s in June, and median annual runoff is 0.32 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 229 to 26,500 ft3/s (median=4,880 ft3/s) (Boughton and others, 2022, table 1-3). About 50 percent of annual peak flows have been in March and April (fig. 19C) associated with the typical snowmelt runoff period. Annual 7-day low flows range from 0 to 305 ft3/s (median=54 ft3/s) (Boughton and oth ers, 2022, table 1-3), and most often are in April through May and July (fig. 19C). At or near-zero streamflows are seldom. The Poplar River originates in Saskatchewan, Canada, and flows southeast for about 125 mi through the Williston Basin to where it enters the Missouri River (figs. 1 and 17). Morrison Dam located on the East Poplar River approxi mately 5 miles upstream from the U.S.-Canadian border, regulates Poplar River streamflows to a small extent; however,
40 Potential Effects of Energy Development, Williston Basin—Water Resources numerous small stock dams and diversion dams are pres ent in the Poplar River Basin. The Poplar River near Poplar, Mont. (streamgage 06181000; contributing drainage area of 3,140 mi2; table 3; fig. 19D), is about 11 mi upstream from the confluence with the Missouri River (fig. 17). In relation to the entire Williston Basin and the other large streams, the Poplar River drainage basin has low mean annual precipita tion (13.9 in.), low mean annual air temperature (39.0 °F), and low percentage of lakes and wetlands (0.6 percent; table 3); these characteristics interact with other drainage basin characteristics and contribute to low drainage basin water yield (3.5 percent; table 3). Median monthly stream flows range from 5.2 ft3/s in January to 161 ft3/s in April, and median annual runoff is 0.31 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 94 to 37,400 ft3/s (median=2,500 ft3/s) (Boughton and others, 2022, table 1-3). About 75 percent of annual peak flows have been in March and April (fig. 19D) associated with the typical snowmelt runoff period. Annual 7-day low flows range from 0 to 39 ft3/s (median=2 ft3/s) (Boughton and others, 2022, table 1-3), and most often are in January through February and August through September (fig. 19D). At or near-zero streamflows are more likely in the winter than in the summer. Large Streams in Northwestern Great Plains The southern and western parts of the Williston Basin are in the Northwestern Great Plains ecoregion (Bryce and others, 1996; Woods and others, 2002). Within the Williston Basin, seven long-term streamgages are on large streams in the Northwestern Great Plains ecoregion: (1) Redwater River at Circle, Mont. (streamgage 06177500); (2) Little Missouri River near Watford City, N. Dak. (streamgage 06337000); (3) Knife River at Hazen, N. Dak. (streamgage 06340500); (4) Heart River near Mandan, N. Dak. (streamgage 06349000); (5) Cannonball River at Breien, N. Dak. (streamgage 06354000); (6) Grand River at Little Eagle, South Dakota (streamgage 06357800); and (7) Moreau River near Whitehorse, S. Dak. (streamgage 06360500) (fig. 17; table 3). Duration hydrographs of daily streamflows are presented in conjunction with annual extreme flows (that is, annual peak-flow and annual 7-day low flow data) for the seven streamgages on large streams in the Northwestern Great Plains ecoregion (fig. 20). The Redwater River originates within the Williston Basin and flows for about 175 mi to its confluence with the Mis souri River (fig. 17). At the confluence with the Missouri, the Redwater River has a drainage area of about 2,100 mi2. The Redwater River is not regulated by major reservoirs, but numerous small stock dams and diversion dams are in the Redwater River drainage basin. The Redwater River at Circle, Mont. (streamgage 06177500; contributing drainage area of 551 mi2; table 3; fig. 20A), is about 60 mi downstream from the Redwater River headwaters and about 115 mi upstream from the confluence with the Missouri River (fig. 17). In relation to the entire Williston Basin and the other large streams, the Redwater River drainage basin has low mean annual precipitation (12.8 in.), high mean annual air tem perature (42.8 °F), and low percentage of lakes and wetlands (0.3 percent; table 3); these characteristics interact with other drainage basin characteristics and contribute to low drainage basin water yield (1.7 percent; table 3). Streamgage 06177500 was included in this study because it provides representa tion of streamflow characteristics for a substantial part of the Williston Basin in the Northwestern Great Plains ecoregion between the main-stem Missouri River and the Yellowstone River. Generally, median duration hydrograph streamflows at streamgage 06177500 are at or near zero throughout most of the year except during a short period from early March through the middle of May (fig. 20A). Median monthly streamflows range from 0.05 ft3/s in September to 8.0 ft3/s in March, and median annual runoff is 0.10 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 2.0 to 6,960 ft3/s (median=214 ft3/s) (Boughton and others, 2022, table 1-3). About 55 percent of annual peak flows have been in February and March (fig. 20A) associated with the typi cal snowmelt runoff period. About 45 percent of annual peak flows have been in May through August from spring and sum mer precipitation. High flows in May through August can have flash-flood characteristics, when streamflows rapidly increase within a few hours from at or near zero to streamflows reach ing several thousand cubic feet per second. Annual 7-day low flows range from 0 to 2.0 ft3/s (median=0 ft3/s) (Boughton and others, 2022, table 1-3). The Little Missouri River originates in northeastern Wyoming, flows northeast for about 100 mi to the southwest ern boundary of the Williston Basin, and then flows for about 590 mi through the Williston Basin to where it enters Lake Sakakawea (fig. 17). The Little Missouri River is not regulated by major reservoirs, but numerous small stock dams and diver sion dams are in the Little Missouri River drainage basin. The Little Missouri River near Watford City, N. Dak. (streamgage 06337000; contributing drainage area of 8,310 mi2; table 3; fig. 20B), is about 50 mi upstream from where the river enters Lake Sakakawea (fig. 17). In relation to the entire Willis ton Basin and the other large streams, the Little Missouri River drainage basin has moderate mean annual precipitation (15.3 in.), high mean annual air temperature (42.9 °F), and low percentage of lakes and wetlands (0.7 percent; table 3); these characteristics interact with other drainage basin characteristics and contribute to moderate drainage basin water yield (5.5 per cent; table 3). Median monthly streamflows range from 2.4 ft3/s in January to 897 ft3/s in March, and median annual runoff is 0.70 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 400 to 52,800 ft3/s (median=10,000 ft3/s) (Boughton and others, 2022, table 1-3). About 50 percent of annual peak flows have been in February and March (fig. 20B) associated with the typical snowmelt runoff period. Annual 7-day low flows range from 0 to 53 ft3/s (median=0 ft3/s) (Boughton and others, 2022, table 1-3). Annual 7-day low flows almost exclusively happen from December through midMarch and routinely are at or near zero (fig. 20B).
River and Stream Resources 41 The Knife River originates within the Williston Basin and flows for about 240 mi from its headwaters to its conflu ence with the Missouri River (fig. 17). The Knife River is not regulated by major reservoirs, but numerous small stock dams and diversion dams are in the Knife River Basin. The Knife River at Hazen, N. Dak. (streamgage 06340500; contributing drainage area of 2,240 mi2; table 3; fig. 20C), is about 25 mi upstream from the confluence of the Knife River with the Mis souri River (fig. 17). In relation to the entire Williston Basin and the other large streams, the Knife River drainage basin has high mean annual precipitation (16.7 in.), moderate mean annual air temperature (41.0 °F), and moderate percentage of lakes and wetlands (1.0 percent; table 3); these characteristics interact with other drainage basin characteristics and contrib ute to high drainage basin water yield (5.9 percent; table 3). Median monthly streamflows range from 17 ft3/s in January to 360 ft3/s in March, and median annual runoff is 0.75 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 100 to 35,300 ft3/s (median=3,900 ft3/s) (Boughton and others, 2022, table 1-3). About 70 percent of annual peak flows have been in February through mid-April (fig. 20C) associated with the typical snowmelt runoff period. Annual 7-day low flows range from 0 to 70 ft3/s (median=10 ft3/s) (Boughton and others, 2022, table 1-3) and most often are in January through mid-March (fig. 20C). At or near-zero stream flows are seldom. The Heart River originates within the Williston Basin and flows for about 320 mi from its headwaters to its conflu ence with the Missouri River (fig. 17). Streamflows of the Heart River are regulated by two major reservoirs, Patterson Lake and Heart Butte Lake (not shown in fig. 1), with mul tipurpose operations that include flood control. In addition, numerous small stock dams and diversion dams are in the Heart River drainage basin. The Heart River near Mandan, N. Dak. (streamgage 06349000; contributing drainage area of 3,310 mi2; table 3; fig. 20D), is about 12 mi upstream from the confluence of the Heart River with the Missouri River (fig. 17). In relation to the entire Williston Basin and the other large streams, the Heart River drainage basin has high mean annual precipitation (16.8 in.), moderate mean annual air temperature (41.0 °F), and moderate percentage of lakes and wetlands (1.0 percent; table 3); these characteristics interact with other drainage basin characteristics and contribute to high drainage basin water yield (6.5 percent; table 3). Median monthly streamflows range from 16 ft3/s in January to 331 ft3/s in March, and median annual runoff is 0.70 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 103 to 29,200 ft3/s (median=3,780 ft3/s) (Boughton and others, 2022, table 1-3). About 60 percent of annual peak flows have been in March and April (fig. 20D) associated with the typical snowmelt runoff period. Annual 7-day low flows range from 0 to 64 ft3/s (median=8.0 ft3/s) (Boughton and others, 2022, table 1-3), almost exclusively happen from December through mid-March (fig. 20D), and occasionally are at or near zero. The Cannonball River originates within the Williston Basin and flows for about 385 mi from its headwaters to its confluence with the Missouri River (fig. 17). The Cannon ball River is not regulated by major reservoirs, but numerous small stock dams and diversion dams are in the Cannon ball River drainage basin. The Cannonball River at Breien, N. Dak. (streamgage 06354000; contributing drainage area of 4,100 mi2; table 3; fig. 20E), is about 35 mi upstream from the confluence of the Cannonball River with the Missouri River (fig. 17). In relation to the entire Williston Basin and the other large streams, the Cannonball River drainage basin has moderate mean annual precipitation (16.6 in.), moderate mean annual air temperature (42.4 °F), and low percentage of lakes and wetlands (1.4 percent; table 3); these characteristics inter act with other drainage basin characteristics and contribute to moderate drainage basin water yield (5.0 percent; table 3). Median monthly streamflows range from 9.6 ft3/s in January to 263 ft3/s in March, and median annual runoff is 0.57 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 374 to 31,100 ft3/s (median=4,100 ft3/s) (Boughton and others, 2022, table 1-3). About 60 percent of annual peak flows have been in March through mid-April (fig. 20E) associ ated with the typical snowmelt runoff period. Annual 7-day low flows range from 0 to 51 ft3/s (median=2.0 ft3/s) (Bough ton and others, 2022, table 1-3), most often are in January through February and August through September (fig. 20E), and often are at or near zero. The Grand River originates within the Williston Basin and flows for about 350 mi from its headwaters to its conflu ence with Lake Oahe (fig. 17). Streamflows of the Grand River are regulated by Shadehill Reservoir (not shown in fig. 1) with multipurpose operations that include flood control. In addi tion, numerous small stock dams and diversion dams are in the Grand River drainage basin. The Grand River at Little Eagle, S. Dak. (streamgage 06357800; contributing drainage area of 5,316 mi2; table 3; fig. 17; fig. 20F), is about 20 mi upstream from the confluence of the Grand River with Lake Oahe (fig. 17). In relation to the entire Williston Basin and the other large streams, the Grand River drainage basin has moderate mean annual precipitation (16.4 in.), high mean annual air temperature (42.8 °F), and moderate percentage of lakes and wetlands (1.2 percent; table 3); these characteristics interact with other drainage basin characteristics and contribute to moderate drainage basin water yield (4.0 percent; table 3). Median monthly streamflows range from 13 ft3/s in January to 361 ft3/s in March, and median annual runoff is 0.37 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 155 to 32,400 ft3/s (median=5,200 ft3/s) (Boughton and others, 2022, table 1-3). About 40 percent of annual peak flows have been in March and early April (fig. 20F) associated with the typical snowmelt runoff period. Annual 7-day low flows range from 0 to 78 ft3/s (median=8.5 ft3/s) (Boughton and others, 2022, table 1-3), most often are in mid-December through mid-February (fig. 20F), and somewhat often are at or near zero. The Moreau River originates within the Williston Basin and flows for about 440 mi from its headwaters to its con fluence with Lake Oahe (fig. 17). The Moreau River is not
42 Potential Effects of Energy Development, Williston Basin—Water Resources regulated by major reservoirs, but numerous small stock dams and diversion dams are in the Moreau River drainage basin. The Moreau River near Whitehorse, S. Dak. (streamgage 06360500; contributing drainage area of 4,872 mi2; table 3; fig. 20G), is about 40 mi upstream from the confluence of the Moreau River with Lake Oahe (fig. 17). In relation to the entire Williston Basin and the other large streams, the Moreau River drainage basin has moderate mean annual precipita tion (16.5 in.), high mean annual air temperature (44.0 °F), and moderate percentage of lakes and wetlands (1.4 percent; table 3); these characteristics interact with other drainage basin characteristics and contribute to moderate drainage basin water yield (4.7 percent; table 3). Median monthly streamflows range from 0.36 ft3/s in January to 301 ft3/s in March, and median annual runoff is 0.39 in. (Boughton and others, 2022, table 1-2). Annual peak flows range from 159 to 34,200 ft3/s (median=5,500 ft3/s) (Boughton and others, 2022, table 1-3). About 30 percent of annual peak flows have been in March and early April (fig. 20G) associated with the typical snowmelt runoff period. Annual 7-day low flows range from 0 to 23 ft3/s (median=0 ft3/s) (Boughton and others, 2022, table 1-3), most often are in January through mid-February and July through September (fig. 20G), and often are at or near zero. Lake and Wetland Resources This section provides information on surface-water features (including saline seeps, wetlands, ponds, and lakes) of the Willison Basin area. Three major reservoirs exist in the Williston Basin and are considered lake resources: Fort Peck Lake, Lake Sakakawea, and Lake Oahe (fig. 17). Metric units are used to present the information described in this section because it is based on earlier work by Preston and ChesleyPreston (2015) who utilized metric units. Spatial Distribution of Lakes and Wetlands Statewide NWI datasets were acquired for Montana, North Dakota, and South Dakota (USFWS, 2014). Spatial distribution information, specifically number, area, and percentage of coverage of NWI features, were calculated for the Williston Basin, the area inside and outside of the Prairie Pothole Region, and for each State and county (fig. 21). The NWI datasets use the full Cowardin classification system to delineate wetlands and deepwater habitats (Cowar din and others, 1979) and provide simplified wetland types. A total of 1,428,501 NWI palustrine and lacustrine features were identified using the Cowardin system within the Willis ton Basin, but these features only encompassed five wetland types (freshwater emergent wetland, freshwater forested/shrub wetland, freshwater pond, lake, and other). The wetland classi fications freshwater emergent wetland and freshwater forested/ shrub wetland were combined into a single wetland category producing a total of four NWI classifications discussed hereafter. These four classifications (collectively referred to as surface-water features), listed by increasing relative size and permanence, are (1) wetland, (2) pond, (3) lake, and (4) other. Because the NWI dataset uses the full Cowardin clas sification, multiple polygons with different classifications can comprise a single surface-water feature, and this commonly results in a single feature appearing as multiple rings or parts. These multiple classifications in one feature were joined to produce a single feature dataset with the objective of keeping the highest NWI classification for all surface-water features within each drainage basin; for example, a multi-ringed wetland was merged into a single feature classified as wetland. Also, ponds and wetlands along a lake margin were merged with the lake and would be reclassified as lake. This polygon collapse process reduced the total number of surface-water features from 1,428,501 to 1,317,519. It is important to note that for the spatial distribu tion calculations a feature that crossed a geographic boundary was counted as a surface-water feature for both geographic units, whereas only the area within each geographic unit was included in the area and percentage of coverage calculations. Within the Williston Basin, the total number, area, and percentage of coverage of surface-water features are greater in the Prairie Pothole Region than the area outside of the region (figs. 1, 21; table 4); for example, the Prairie Pothole Region (78,240 square kilometers [km2]) covers only 28.9 percent of the Williston Basin (270,589 km2) (fig. 21) yet contains three times the number of surface-water features as the area outside the region. Despite having nearly three-quarters of all surfacewater features within the Williston Basin, the area of surfacewater features in the Prairie Pothole Region is only 1.2 times greater than the area of surface-water features outside the region, mainly because several large lakes along the Mis souri River exist outside the region. Finally, the percentage of the landscape covered by surface-water features is 2.9 times greater within the Prairie Pothole Region compared to the area outside the region (table 4). The spatial distribution of surface-water features also varied among Montana, North Dakota, and South Dakota (table 5). Although the area of North Dakota in the Wil liston Basin is only 1.4 times larger than that of Montana (128,189 and 91,577 km2, respectively), North Dakota has more than 6.6 times as many surface-water features as Montana (1,087,789 and 164,503 surface-water features, respectively). Similarly, the area of North Dakota in the Williston Basin is only 2.7 times greater than South Dakota (47,266 km2), yet it has 16.6 times as many surface-water features (1,087,789 and 65,342 surface-water features, respec tively). North Dakota also has more than 4.1 and 8.3 times the area of surface-water features (9,088 km2) compared to Montana (2,188 km2) and South Dakota (1,095 km2) (table 5). The percentage of coverage of surface-water features is about 1.9 and 2.9 times greater in North Dakota (7 percent) com pared to Montana (2.3 percent) and South Dakota (1.2 percent) (table 5).
Lake and Wetland Resources 43 Figure 21. Proximity of surface-water features to oil and gas wells in the Williston Basin. ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! ! 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! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! 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! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! 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! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 100° 105° 110° 48° 45° MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA Williston Basin boundary Prairie Pothole Region boundary Surface-water feature—Data from U.S. Fish and Wildlife Service (2014) County line ! Oil or gas well EXPLANATION UNITED STATES CANADA 100 MILES 100 KILOMETERS Base map modified from U.S. Geological Survey, Esri, Montana Board of Oil and Gas, North Dakota Oil and Gas Division, South Dakota Department of Enviornmental and Natural Resources digital data, variously dated, various scales. Well data current as of July, 2016. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum 1983
44 Potential Effects of Energy Development, Williston Basin—Water Resources Table 4. The total number, area, and percentage of coverage of surface-water features, not including streams and rivers, for the Williston Basin and the parts of the Williston Basin inside and outside of the Prairie Pothole Region. greater than] Williston Basin Inside Prairie Pothole Region Outside Prairie Pothole Region Total number Area, in square kilometers Coverage of surfacewater feature, in percent Total number Area, in square kilometers Coverage of surfacewater feature, in percent Total number Area, in square kilometers Coverage of surfacewater feature, in percent Wetland 1,190,460 4,895 953,147 3,743 237,745 1,157 Pond 117,254 1,967 32,007 1,120 85,297 Lake 3,254 5,486 2,520 1,907 3,694 Other 6,551 6,172 Total 1,317,519 12,371 988,055 6,772 329,963 5,721 Table 5. The total number, area, and percentage of coverage of surface-water features, not including streams and rivers, for the parts of Montana, North Dakota, and South Dakota within the Williston Basin. greater than] Montana North Dakota South Dakota Total number Area, in square kilometers Coverage of surfacewater feature, in percent Total number Area, in square kilometers Coverage of surfacewater feature, in percent Total number Area, in square kilometers Coverage of surfacewater feature, in percent Wetland 128,033 1,025,931 4,046 36,568 Pond 35,392 56,680 1,319 25,210 Lake 1,216 2,701 3,717 Other 2,477 3,357 Total 164,503 2,188 1,087,789 9,088 65,342 1,095 Finally, the spatial distribution of surface-water features varied among individual counties within the Williston Basin area (figs. 21, 22). A total of 72 counties are located wholly or partially within the Williston Basin area with the total number, area, and percentage of coverage of surface-water features for the top 25 ranked counties in each of these three categories shown in figure 22. Ward County, N. Dak., contains the greatest total number of surface-water features (92,190), whereas Petroleum County, Mont., contains the least (10) (fig. 22; Boughton and others, 2022, table 2-1). In terms of total area of all surface-water features, McLean County, N. Dak., contains the greatest area (922.1 km2), whereas Rosebud County, Mont., contains the least (1.2 km2) (Boughton and others, 2022, table 2-2). Ramsey County, N. Dak., has the greatest percentage of coverage of total surface-water features (33.2 percent), whereas Billings County, N. Dak., has the least (0.2 percent) (Boughton and others, 2022, table 2-3). The number, area, and percentage of coverage of surface-water features by county for each State are provided in data release tables 2-1, 2-2, and 2-3, respectively (Boughton and others, 2022). Proximity of Lakes and Wetlands to Energy Development The Williston Basin contains a large amount of energy development infrastructure as indicated by the presence of oil and gas wells (fig. 21), which can be near surface-water features. The collapsed surface-water feature NWI dataset (described in the previous section) was analyzed in relation to the oil and gas well databases from the Montana Board of Oil and Gas Conservation, the North Dakota Industrial Commis sion, and the South Dakota Department of Environment and Natural Resources (SDDENR) to investigate the proximity of
Lake and Wetland Resources 45 Valley, Mont. Emmons, N. Dak. Foster, N. Dak. Eddy, N. Dak. Logan, N. Dak. Williams, N. Dak. Blaine, Mont. Burleigh, N. Dak. Kidder, N. Dak. Towner, N. Dak. Phillips, Mont. Divide, N. Dak. Sheridan, N. Dak. Pierce, N. Dak. Wells, N. Dak. Rolette, N. Dak. Burke, N. Dak. Stutsman, N. Dak. Renville, N. Dak. McHenry, N. Dak. Mountrail, N. Dak. McLean, N. Dak. Benson, N. Dak. Bottineau, N. Dak. Ward, N. Dak. 50,000 100,000 Corson, S. Dak. Dewey, S. Dak. Dunn, N. Dak. Wells, N. Dak. Rolette, N. Dak. Divide, N. Dak. Emmons, N. Dak. Sheridan, N. Dak. Burke, N. Dak. McKenzie, N. Dak. Williams, N. Dak. Logan, N. Dak. Bottineau, N. Dak. Burleigh, N. Dak. Pierce, N. Dak. Benson, N. Dak. Phillips, Mont. Ward, N. Dak. Valley, Mont. Garfield, Mont. McHenry, N. Dak. Kidder, N. Dak. Stutsman, N. Dak. Mountrail, N. Dak. McLean, N. Dak. 1,000 McPherson, S. Dak. Wells, N. Dak. Ward, N. Dak. Foster, N. Dak. Burleigh, N. Dak. Divide, N. Dak. Towner, N. Dak. Campbell, S. Dak. Burke, N. Dak. McHenry, N. Dak. Sheridan, N. Dak. Mountrail, N. Dak. Eddy, N. Dak. Rolette, N. Dak. Benson, N. Dak. Stutsman, N. Dak. LaMoure, N. Dak. Logan, N. Dak. Pierce, N. Dak. Kidder, N. Dak. Stanley, S. Dak. McLean, N. Dak. Walworth, S. Dak. Petroleum, Mont. Ramsey, N. Dak. Number of surface-water features Area of surface-water features, in square kilometers Surface-water coverage, in percent Figure 22. Summary statistics of surface-water features, not including streams and rivers, for the top 25 counties in the Williston Basin, ranked by total number of surface-water features, total area of surface-water features, and the percentage of the County covered by surface-water features. surface-water features to energy-related wells. All oil or gas well data were acquired on March 11, 2015, and only wells that had drilling completed by this date were selected, result ing in a total of 41,535 wells. Proximity analyses to determine the number, area, and percentage of surface-water features within 0.4, 0.8 and 1.6 kilometers (km) of at least one oil or gas well were completed for the Williston Basin, the area inside and outside of the Prairie Pothole Region (table 6), and each State and County (Boughton and others, 2022, tables 2-4, 2-5, and 2-6). The number and area of surface-water features near oil or gas wells was calculated by first determining a buffer around each surface-water feature at 0.4, 0.8 and 1.6 km. Next, the surface-water features were clipped to the geographic extents of the proximity analyses of the area inside and outside the Prairie Pothole Region and the area of each State and County. The area of the surface-water features was recalculated before each analysis, and the total number and area of surface-water features were summed for each geographic extent. If a surfacewater feature crossed a geographic boundary but was near an oil or gas well anywhere around its perimeter, the feature was included in the total number of surface-water features near wells for both extents; however, only the area in the given extent was calculated. Similarly, if a surface-water feature was within a given extent yet was near an oil or gas well outside that extent, the feature was still included in the total number and area of surface-water features for that extent. The percent age of surface-water features near oil and gas wells was cal culated by dividing the total number of surface-water features near wells within each buffer distance by the total number of surface-water features within each geographic extent. Across the Williston Basin, most oil or gas wells (98.7 percent) are within 1.6 km of surface-water features, whereas most surface-water features (69.6 percent) were not near oil or gas wells; however, this number will likely decrease with expected future development. Although many surface-water features are near only one well, some surfacewater features are near numerous oil and gas wells, and some wells are near numerous surface-water features. The proximity of surface-water features to oil and gas wells in the Williston
46 Potential Effects of Energy Development, Williston Basin—Water Resources Table 6. Total number, area, and percentage of surface-water features, not including streams and rivers, near (0.4, 0.8, and 1.6 kilometers) oil and gas wells in the Williston Basin and the parts of the Williston Basin inside and outside of the Prairie Pothole Region. Type 0.4-kilometer buffer 0.8-kilometer buffer 1.6-kilometer buffer Total number Area, in square kilometers Surface-water features near oil and gas wells, in percent Total number Area, in square kilometers Surface-water features near oil and gas wells, in percent Total number Area, in square kilometers Surface-water features near oil and gas wells, in percent Williston Basin Wetland 82,704 191,385 367,491 1,327 Pond 7,345 15,821 30,708 Lake 1,901 2,042 1,000 2,262 Other 1,795 Total 90,770 2,455 208,685 3,066 400,994 4,100 Inside Prairie Pothole Region Wetland 65,358 151,741 293,087 1,000 Pond 2,328 5,053 9,870 Lake Other Total 67,956 157,301 1,120 303,872 1,903 Outside Prairie Pothole Region Wetland 17,382 39,726 74,552 Pond 5,020 10,779 20,854 Lake 1,580 1,598 1,621 Other 1,647 Total 22,855 1,790 51,479 1,946 97,289 2,197 Basin was different inside and outside the Prairie Pothole Region (fig. 21; table 6). The Prairie Pothole Region covers only 28.9 percent of the Williston Basin (fig. 21) and contains only 29.1 percent (12,087) of the total identified oil and gas wells (41,535); however, the Prairie Pothole Region contains about three times as many surface-water features near oil and gas wells in all three buffer distances (0.4, 0.8, and 1.6 km) as compared to the area outside the region (fig. 21; table 6). Although the area outside the Prairie Pothole Region contains fewer surface-water features near oil and gas wells, the area of these surface-water features was greater in all three buffer dis tances compared to area inside of the region, mainly because of the presence of several large lakes along the Missouri River outside of the region. Finally, the percentage of surfacewater features near oil and gas wells was similar for the areas inside and outside of the Prairie Pothole Region (table 6). This reflects the fact that there are about three times as many surface-water features inside the Prairie Pothole Region com pared to the area outside the region. A more thorough analysis on the proximity of surface-water features to oil and gas wells for the Prairie Pothole Region is provided in Tangen and oth ers (2014). The proximity of surface-water features to oil and gas wells also varied among States (table 7). North Dakota has about 2.1 and 24.7 times as many oil and gas wells as Montana and South Dakota, respectively; however, it also has 6.5 and 16.6 times as many surface-water features, respectively. Additionally, the total number and area of surface-water fea tures near oil and gas wells in North Dakota are much greater than Montana and South Dakota in all three buffer distances. Similarly, Montana has a much greater number of wells and surface-water features compared to South Dakota and, therefore, a greater total number and area of surface-water features near oil and gas wells. Notably, the percentage of surface-water features near oil and gas wells in all three buffer distances was highest in Montana, followed by North Dakota and South Dakota. The number and proximity of surface-water features to oil and gas wells also varied among individual counties within the Williston Basin (Boughton and others, 2022, tables 2-4, 2-5, 2-6). The total number, area, and percentage of surfacewater features near wells for the top 25 ranked counties in each of these three buffer distances are shown on figures 23, 24, and 25. Renville County, N. Dak., had the greatest total number
Quality of Water Resources 47 Table 7. Total number, area, and percentage of surface-water features, not including streams and rivers, near (0.4, 0.8, and 1.6 kilometers) oil and gas wells in the parts of Montana, North Dakota, and South Dakota in the Williston Basin. Type 0.4-kilometer buffer 0.8-kilometer buffer 1.6-kilometer buffer Total number Area, in square kilometers Surface-water features near oil and gas wells, in percent Total number Area, in square kilometers Surface-water features near oil and gas wells, in percent Total number Area, in square kilometers Surface-water features near oil and gas wells, in percent Montana Wetland 11,412 23,092 44,687 Pond 2,538 4,996 9,735 Lake Other Total 14,144 28,411 54,968 North Dakota Wetland 70,960 167,324 320,136 1,079 Pond 4,481 9,982 18,877 Lake 1,750 1,868 2,044 Other Total 75,884 2,113 178,202 2,612 340,610 3,431 South Dakota Wetland 2,700 Pond 2,108 Lake Other Total 2,103 5,468 of surface-water features near oil and gas wells in each of the three buffer distances (14,692 [0.4-km buffer; fig. 23], 32,362 [0.8-km buffer; fig. 24], and 51,195 [1.6-km buffer; fig. 25]; Boughton and others, 2022, table 2-4). McLean County, N. Dak., had the greatest area of surface-water features near oil and gas wells in each of the three buffer distances (455.2 km2 [0.4-km buffer; fig. 23], 465.5 km2 [0.8-km buffer; fig. 24], and 487.7 km2 [1.6-km buffer; fig. 25]; Boughton and others, 2022, table 2-5). McKenzie County, N. Dak., had the great est percentage of surface-water features near oil and gas wells in the 0.4-km buffer (34.0 percent; fig. 23) and 0.8-km buffer (62.9 percent; fig. 24), whereas Liberty County, Mont. had the greatest percentage in the 1.6-km buffer of a well (92.3 percent; fig. 25) (Boughton and others, 2022, table 2-6). No surfacewater features were within the 0.4-km buffer for five counties: Petroleum and Rosebud Counties, Mont.; LaMoure County, N. Dak.; and McPherson and Pennington Counties, S. Dak. Three of these counties (Petroleum, LaMoure, and McPherson Coun ties) had no surface-water features within 0.8 or 1.6 km of an oil or gas well either. Quality of Water Resources Numerous local, State, Tribal, and Federal agencies have been collecting water-quality data within the Williston Basin for decades. Other water-quality monitoring, such as that completed by private industry, may often be proprietary and not available to the public. Water-quality samples have been collected from groundwater, springs, streams, rivers, lakes, reservoirs, storm water, wastewater discharge points, and other surface-water and groundwater features. Samples were collected for several reasons including compliance monitoring, after known pollutant releases (for example, spills), or char acterization of water-quality conditions of a particular water resource. The types of data collected, the sample collection protocols, analytical methods, and reporting processes differ greatly. As such, the availability of consistently collected, systematically processed and reported data over large parts of the Williston Basin is sparse; however, a substantial amount of water-quality data is available that provides insight regarding the condition of the water quality within the Williston Basin.
48 Potential Effects of Energy Development, Williston Basin—Water Resources Benson, N. Dak. Pierce, N. Dak. Valley, Mont. Rolette, N. Dak. Stark, N. Dak. McLean, N. Dak. Harding, S. Dak. Bowman, N. Dak. Billings, N. Dak. Richland, Mont. Roosevelt, Mont. McHenry, N. Dak. Blaine, Mont. Dunn, N. Dak. Sheridan, Mont. Fallon, Mont. McKenzie, N. Dak. Ward, N. Dak. Williams, N. Dak. Phillips, Mont. Divide, N. Dak. Mountrail, N. Dak. Burke, N. Dak. Bottineau, N. Dak. Renville, N. Dak. Number of surface-water features 20,000 40,000 60,000 Dawson, Mont. Slope, N. Dak. Blaine, Mont. Wibaux, Mont. Harding, S. Dak. Ward, N. Dak. Golden Valley, N. Dak. Hill, Mont. Stark, N. Dak. Roosevelt, Mont. Bowman, N. Dak. Dunn, N. Dak. Phillips, Mont. Divide, N. Dak. Sheridan, Mont. Richland, Mont. Fallon, Mont. Mountrail, N. Dak. Williams, N. Dak. Bottineau, N. Dak. Burke, N. Dak. Renville, N. Dak. Liberty, Mont. Billings, N. Dak. McKenzie, N. Dak. Ziebach, S. Dak. Richland, Mont. Dewey, S. Dak. Valley, Mont. Stark, N. Dak. Rolette, N. Dak. Pierce, N. Dak. Roosevelt, Mont. Blaine, Mont. Fallon, Mont. Ward, N. Dak. Hill, Mont. Divide, N. Dak. McHenry, N. Dak. Renville, N. Dak. Sheridan, Mont. Bottineau, N. Dak. Burke, N. Dak. Phillips, Mont. Mercer, N. Dak. Dunn, N. Dak. Williams, N. Dak. McKenzie, N. Dak. Mountrail, N. Dak. McLean, N. Dak. Area of surface-water features, in square kilometers Surface-water features, in percent Figure 23. The top 25 counties wholly or partially in the Williston Basin, ranked by total number, area, and percentage of surface-water features within 0.4 kilometer of at least one oil or gas well. Water-Quality Data Consolidation Water-quality monitoring associated with energy devel opment is typically coordinated at the State level, and acces sibility of these data differs by State (Bowen and others, 2015). Most data used to characterize water-quality within the Williston Basin, data were obtained from the Water-Quality Portal (WQP) (National Water Quality Monitoring Council [NWQMC], 2015). Additional data was acquired as part of the USGS's National Water Quality Assessment (NAWQA) Program's data compilation with processing steps used to identify river and stream sites throughout the Nation with samples suitable for water-quality, pesticide, and ecology trend analysis (Oelsner and others, 2017). The WQP is a cooperative service sponsored by the USGS, the EPA, and the NWQMC. The WQP integrates pub licly available water-quality data through an exchange from the USGS NWIS database (USGS, 2015c), the EPA Storage and Retrieval (STORET) data warehouse (EPA, 2015), and the U.S. Department of Agriculture (USDA) Sustaining The Earth's Watersheds—Agricultural Research Data System (STEWARDS) (Steiner and others, 2008). The WQP retrieves water-quality data from more than 400 Federal, State, Tribal, and local databases. The WQP had 252 million records as of 2015 and contains water-quality data, including physical mea surements and chemical and biological metadata (NWQMC, 2015). The data compilation for the NAWQA project was completed during 2012 and 2013 and was an aggregation of water-quality data from Federal, State, and local agencies that was not available in the EPA STORET data warehouse, USGS NWIS database, or other nationally available databases (Oel sner and others, 2017). The water-quality data were compiled from western states and provided results from early 1938 through 2014. Data from the WQP and the NAWQA project compilation were combined and used, in part, to identify for further evalua tion, 5 commonly monitored water-quality field measurements or constituents (hereafter referred to as "primary constitu ents") along with 10 trace metals common in produced waters (Guerra and others, 2011; EPA, 2012; Galloway and others, 2012). Collectively, this extensive quality-control review will result in an updated, more accurate dataset for future analyses of the selected water-quality constituents. The dataset will serve as a solid foundation for an initial review of selected
Quality of Water Resources 49 Valley, Mont. Benson, N. Dak. Stark, N. Dak. Bowman, N. Dak. Pierce, N. Dak. Billings, N. Dak. Harding, S. Dak. Rolette, N. Dak. McLean, N. Dak. Richland, Mont. Roosevelt, Mont. Dunn, N. Dak. Fallon, Mont. Blaine, Mont. McHenry, N. Dak. Sheridan, Mont. McKenzie, N. Dak. Phillips, Mont. Williams, N. Dak. Ward, N. Dak. Divide, N. Dak. Mountrail, N. Dak. Burke, N. Dak. Bottineau, N. Dak. Renville, N. Dak. Number of surface-water features 20,000 40,000 60,000 Harding, S. Dak. Logan, N. Dak. Stark, N. Dak. Valley, Mont. Richland, Mont. Roosevelt, Mont. Rolette, N. Dak. Fallon, Mont. Blaine, Mont. Pierce, N. Dak. Hill, Mont. Ward, N. Dak. McHenry, N. Dak. Renville, N. Dak. Sheridan, Mont. Divide, N. Dak. Phillips, Mont. Bottineau, N. Dak. Burke, N. Dak. Mercer, N. Dak. Dunn, N. Dak. Williams, N. Dak. McKenzie, N. Dak. Mountrail, N. Dak. McLean, N. Dak. Valley, Mont. Wibaux, Mont. Blaine, Mont. Slope, N. Dak. Harding, S. Dak. Ward, N. Dak. Golden Valley, N. Dak. Stark, N. Dak. Hill, Mont. Fallon, Mont. Roosevelt, Mont. Phillips, Mont. Bowman, N. Dak. Sheridan, Mont. Dunn, N. Dak. Richland, Mont. Divide, N. Dak. Mountrail, N. Dak. Bottineau, N. Dak. Williams, N. Dak. Burke, N. Dak. Billings, N. Dak. Renville, N. Dak. Liberty, Mont. McKenzie, N. Dak. Surface-water features, in percent Area of surface-water features, in square kilometers Figure 24. The top 25 counties wholly or partially in the Williston Basin, ranked by total number, area, and percentage of surface-water features within 0.8 kilometer of at least one oil or gas well. water-quality constituents in the Williston Basin, and provide a tool to compliment current and future water-quality monitor ing programs. These data may provide background informa tion useful for evaluating effects of energy development. Development of Water-Quality Dataset Water-quality data were retrieved from the WQP for each County within the Williston Basin for samples of groundwater, springs, streams, rivers, lakes, reservoirs, and wetlands. The retrieved data included samples collected from 1900 to 2015. Water-quality data were retrieved from the NAWQA data compilation for sites in Montana, North Dakota, and South Dakota. For each site sampled in either dataset that included locational information (latitude/longitude), those sites within the boundary of the Williston Basin were selected for further analyses. The two datasets were then aggregated to form one primary dataset that could be used to characterize available data for the Williston Basin. This dataset was initially culled, which included, in part, removing known duplicate sites or samples and known quality-control samples (for example, blank and replicate samples). In addition, numerous constituents had multiple naming conventions (for example, "total dissolved solids," or "TDS," or "solids, dissolved"). Once a constituent or measure ment was selected for more detailed analyses, a consistent name was selected and used. Additional refinement, further discussed below, was not trivial and involved extensive review and quality-control checks. Although data were synthesized for groundwater, springs, streams, rivers, lakes, reservoirs, and wetlands, focus was placed on three groundwater and surface-water features: (1) groundwater; (2) streams and rivers (combined); and (3) lakes and reservoirs (combined). Data in WQP and the NAWQA project's data compilation included samples col lected since the early 1900s, but the number of samples collected increased in the early 1970s in groundwater and streams/rivers, presumably because of implementation of the Clean Water Act of 1972 (EPA, 1972). While data for samples collected in 2015 were available, the period from 1970 through 2014 was selected for further analyses. This period includes a timeframe during the peak of conventional oil production (late 1970s), and timeframes before and during
50 Potential Effects of Energy Development, Williston Basin—Water Resources Bowman, N. Dak. Valley, Mont. Burleigh, N. Dak. Wells, N. Dak. Richland, Mont. Harding, S. Dak. Benson, N. Dak. Pierce, N. Dak. Roosevelt, Mont. Fallon, Mont. McLean, N. Dak. Dunn, N. Dak. Rolette, N. Dak. McKenzie, N. Dak. Sheridan, Mont. Blaine, Mont. McHenry, N. Dak. Phillips, Mont. Williams, N. Dak. Divide, N. Dak. Ward, N. Dak. Mountrail, N. Dak. Burke, N. Dak. Bottineau, N. Dak. Renville, N. Dak. 20,000 40,000 60,000 Number of surface-water features Wells, N. Dak. Richland, Mont. Valley, Mont. Stutsman, N. Dak. Burleigh, N. Dak. Fallon, Mont. Roosevelt, Mont. Hill, Mont. Rolette, N. Dak. Blaine, Mont. Pierce, N. Dak. Renville, N. Dak. Sheridan, Mont. Ward, N. Dak. McHenry, N. Dak. Mercer, N. Dak. Phillips, Mont. Bottineau, N. Dak. Divide, N. Dak. Dunn, N. Dak. Burke, N. Dak. Williams, N. Dak. McKenzie, N. Dak. Mountrail, N. Dak. McLean, N. Dak. Daniels, Mont. Wibaux, Mont. Blaine, Mont. Slope, N. Dak. Harding, S. Dak. Ward, N. Dak. Fallon, Mont. Golden Valley, N. Dak. Stark, N. Dak. Phillips, Mont. Bowman, N. Dak. Hill, Mont. Roosevelt, Mont. Richland, Mont. Sheridan, Mont. Mountrail, N. Dak. Dunn, N. Dak. Bottineau, N. Dak. Divide, N. Dak. Burke, N. Dak. Williams, N. Dak. Billings, N. Dak. Renville, N. Dak. McKenzie, N. Dak. Liberty, Mont. Surface-water features, in percent Area of surface-water features, in square kilometers Figure 25. The top 25 counties wholly or partially in the Williston Basin, ranked by total number, area, and percentage of surface-water features within 1.6 kilometers of at least one oil or gas well. the increased use of hydraulic fracturing for unconventional oil and gas development in the Williston Basin (mid-2000s). The total and cumulative number of stream and river samples collected per year is shown on figure 26 (a similar pattern was observed for groundwater samples). The reduction in samples beginning in about 2012 may, in part, be attributed to an agency delay loading the data to the database. Selection of Water-Quality Data for Analyses A total of 289, 498, and 334 individual constituents were analyzed in groundwater, streams and rivers, and lakes and reservoirs, respectively, regardless of the naming convention, constituent fraction type, or reported unit types. Summaries of the constituents analyzed in groundwater, streams and rivers, and lakes and reservoirs are available in a data release (Boughton and others, 2022, tables 3-1, 3-2, 3-3). The data included, in part, field measurements, major ions, trace ele ments, nutrients, volatile organic compounds, pesticides, and other physical properties. Collectively, this information was used to identify five commonly monitored water-quality constituents: (1) specific conductance, (2) TDS, (3) pH, (4) sulfate, and (5) chloride. These constituents were among the most commonly measured in all three groundwater and surface-water features (groundwater, streams and rivers, and lakes and reservoirs) and also are considered important with respect to the quality of produced water in the Williston Basin. Selected constituent concentrations in the water-quality data were compared to EPA drinking-water maximum contam inant levels (MCLs), secondary maximum contaminant levels (SMCLs), and action levels (ALs) (EPA, 2009, 2012). An MCL is an enforceable standard that refers to the highest level or concentration that is allowed in drinking water supplied by public water systems for protection of health. An SMCL is a nonenforceable guideline and addresses either cosmetic or aesthetic effects, such as taste, odor, and color. An AL is the concentration of copper or lead in drinking water at or above which additional steps are required to reduce the constituent concentration (EPA, 2009, 2012). For regulatory purposes, the AL is applied only to tap water samples, and only if more than 10 percent of the samples exceeded the AL. In total, 10 secondary water-quality constituents, all trace metals, also were selected for evaluation because they are
Quality of Water Resources 51 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 1,500 2,000 2,500 3,000 3,500 Cumulative number of surface-water samples
Number of surface-water samples
Water year
Rivers and streams (combined) Cumulative river and streams Cumulative river and streams (1970-2014) 1,000 EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Figure 26. Number of stream and river samples collected in the Williston Basin, 1970 through 2015. common in produced waters, have comparable EPA drinkingwater standards, and were used for evaluation of water-quality characteristics for streams in North Dakota (Guerra and others, 2011; EPA, 2009, 2012; Galloway and others, 2012). The 10 secondary constituents were aluminum, arsenic, barium, chromium, copper, iron, lead, selenium, strontium, and zinc. Although the period of 1970 through 2014 was used for evalua tion of the 5 commonly monitored constituents, the period from 1993 through 2014 was used for evaluation of the 10 secondary trace metal constituents because there were substantial changes in sample collection and analytical methods for these constitu ents beginning in 1993 (USGS, 1992, 1993). Proper and consistent use of reporting units determined if water-quality data were retained for evaluation; for example, specific conductance values only were retained if the units were identified as microsiemens per centimeter at 25 degrees Celsius (µS/cm). TDS concentrations were retained if reported as either measured or calculated; however, when both types of data were available, precedence was placed on measured concentrations. Values for pH were reported as either "pH" or "pH (lab)," and when values were reported for both, precedence was placed on using values recorded as "pH." Only the analyses for chloride, sulfate, and the 10 secondary constituents from the dissolved fraction of samples were retained. Concentrations for constitu ents with multiple reporting units were adjusted to the most common reporting unit. Sulfate only was evaluated if the units were identified as milligrams per liter as sulfate. Censoring levels, such as "less than," often are used when constituent concentrations are too low to be accurately quanti fied. Many of the constituents have a wide range of analyti cal censoring levels for numerous reasons. Censoring levels can change through time and among laboratories because of changes in sensitivity of laboratory equipment or analytical methods or changes in protocol for determining the censoring level. The censoring level is generally higher than the method detection limit, which is the lowest concentration for which a compound can be detected (but not necessarily accurately quantified) (Childress and others, 1999). Determination of a common assessment level among the reporting levels for each constituent evaluated was beyond the scope of this report. Sampling locations that had an analytical value for at least one of the five commonly monitored constituents (specific conductance, TDS, pH, sulfate, and chloride) became likely candidates for retention and further analysis. Duplicate analy ses were common for some sampling locations. In the case of true duplicate (quality-control) samples, the latter samples were removed from the database. Often, the same sampling location was sampled by multiple agencies on different dates and times, and each agency used their own sampling site name or identi fier for the same location. All groundwater, streams and rivers, and lakes and reservoir locations were evaluated to ensure that each sampling location was identified uniquely. Collectively, this extensive quality-control review and application resulted in an updated, more accurate dataset for future analyses of the constituents (Boughton and oth ers, 2022). It is important to note that the dataset may require further refinement to improve accuracy, but this refinement is beyond the scope of this study. Some values that remain in the dataset are questionable and not likely representative of true environmental conditions; however, they are publicly available from the WQP (National Water Quality Monitoring Council, 2015), the USGS NAWQA data compilation (Oel sner and others, 2017), or the Montana Bureau of Mines and Geology (Montana Bureau of Mines and Geology, 2021). As such, some minimum and maximum values or concentrations may be lower or higher than actual values. Median values or concentrations are likely to be representative of environmental conditions. This is an important consideration for future use of this dataset, especially for constituents not summarized in this report. Regardless, the resultant dataset will serve as a solid basis for an initial review of selected water-quality results in the Williston Basin and provides important information to com pliment current and future water-quality monitoring programs.
52 Potential Effects of Energy Development, Williston Basin—Water Resources Groundwater Data Each groundwater site was examined for locational information, aquifer screening information, and depth com ponent (well completion depth, bottom of screened interval, or sample collection depth) information. If a groundwater site was within 100 meters of another site with the same aquifer name, the well completion depth and screened intervals were compared. If well depths, or screened intervals, for the sites were within 5 meters, the sites were considered the same site, and data from both sites were combined. If a USGS station identifier was present for one of the duplicate sites, the USGS identifier was selected as the preferred station identifier for combining the data from the sites, and duplicate water-quality data were removed. No duplicate groundwater site identifiers were detected even though more than one agency will occa sionally monitor the same well. Duplicates were not detected because likely duplicate candidates did not have the required ancillary information to be included: aquifer sampled or depth component. In total, 25 categories of groundwater samples were documented in the primary database. These included, in part, those coded as plugged, unused, destroyed, or unknown. The importance of data from these types of wells is uncertain; there fore, emphasis was placed solely on those coded as domestic, municipal, observation, industrial, production, stock, and well. Only samples from wells screened in a known aquifer with locational information (latitude and longitude) and a known depth (well completion depth, bottom of screened interval, or sample collection depth) were retained for analyses. In total, samples were collected from 295 uniquely coded aquifers dur ing 1970 through 2014 (Boughton and others, 2022, table 3-4). Samples were grouped based on four categories of aquifer sys tems: (1) Quaternary unconsolidated (including the alluvial and glacial aquifers/aquifer system); (2) lower Tertiary; (3) Upper Cretaceous; and (4) unknown/deeper (Boughton and others, 2022, table 3-4). Only samples from the Quaternary uncon solidated aquifers, and lower Tertiary and Upper Cretaceous aquifer systems were evaluated. Samples from 7,502 wells were evaluated for at least 1 of the 5 commonly monitored constitu ents, including 3,194 in the Quaternary unconsolidated, 2,505 in the lower Tertiary, and 1,803 in the Upper Cretaceous aquifer systems. A list of the groundwater sites by aquifer is available in a data release (Boughton and others, 2022, table 3-5). River and Streams Data For river and stream locations, sites were investigated further if they were within 100 meters of each other. The site names were compared to determine if the sites were on the same waterbody. If the site names were not descriptive, a GIS coverage with the NHD stream reaches was used to determine the waterbody. If there was a USGS station identifier for one of the duplicate sites, the USGS site identifier was selected as the preferred station identifier for combining the data from the sites, and duplicate water-quality data were removed. Eight categories of river and stream samples were docu mented in the primary database including: (1) canal irrigation; (2) ditch or canal; (3) facility municipal sewage; (4) irrigation and returns; (5) river/stream; (6) stream; (7) stream:canal; or (8) stream:ditch. Similar to groundwater, the importance of data from some of these categories is uncertain; therefore, emphasis was placed on those coded as river/stream and stream. Rivers and streams have greater temporal variability than groundwater and lakes. As such, it was determined that for a stream and river site to be further evaluated, it needed to be sampled at least 10 times from 1970 through 2014. After aggregating all duplicate sites, those sites with fewer than 10 samples for any of the 5 commonly monitored constituents were removed, resulting in 329 sites available for river and stream water-quality characterization (Boughton and others, 2022, table 3-6). Lakes and Reservoirs Data For lakes and reservoirs locations, if a site was within 100 meters of another site, further investigation was war ranted. The site names were compared to determine if the sites were on the same waterbody. If the site names were not descriptive, a GIS coverage was used to determine if the sites were on the same waterbody. If there was a USGS station identifier for the one of the duplicate sites, the USGS site identifier was selected as the preferred station identifier for combining the data from the sites, and duplicate water-quality data were removed. Four categories of lakes and reservoir samples were doc umented in the primary database including (1) lake; (2) lake/ reservoir/impoundment; (3) reservoir; and (4) pond. Again, the importance of some of these types of sites is uncertain; there fore, emphasis was placed on those coded as lakes, reservoirs, and lake/reservoir/impoundments. Hereafter, samples from "lakes and reservoirs" will be referred to as samples from "lakes." For lakes, samples often are collected at different depths. For the purposes of this report, if samples were collected at different depths from the same site on the same date and time, the values for properties other than pH were averaged. For pH, the mean value of all depths at a location was used. The mean was determined by calculating the mean hydrogen ion activity value for each location and converting back into standard pH units. After aggregating duplicate sites, 839 lake sites were available for data characterization (Boughton and others, 2022, table 3-7). Characterization of Water Quality in the Williston Basin Water-quality data are presented in a broad framework. The five commonly monitored constituents (specific con ductance, TDS, pH, sulfate, and chloride) were analyzed
Quality of Water Resources 53 graphically through use of bubble plots to characterize break points in measurements or concentrations, as determined from a GIS coverage. This analysis also incorporated a characteriza tion of the number of oil or gas wells in the Williston Basin. In the case of streams and rivers, and lakes and reservoirs, the number of oil and gas wells are presented within USGS eight-digit Hydrologic Unit Codes (HUC-8; U.S. Geological Survey, 2015a). A second graphical representation used box plots, which are graphical representations of statistical values of concentrations (TIBCO Software, Inc., 2014). Tabular analyses including summary statistics for each of the five commonly monitored constituents have been pub lished in a data release. The data release contains analyses for groundwater resources (Boughton and others, 2022, tables 3-8 to 3-12), streams and rivers (Boughton and others, 2022, tables 3-16 to 3-20), and lakes (Boughton and others, 2022, tables 3-22 to 3-31), along with summary statistics for the 10 trace metals (tables 8, 9, 10; Boughton and others, 2022, tables 3-13 through 3-15, 3-21, 3-32). In all cases, figures and statistical summaries were calculated with no consider ation for period of record, sampling dates (other than during 1970 through 2014), sampling times, or censoring levels. Measurements or concentrations that were less than detection levels (non-detections) were not included in the statistical summaries. Groundwater Quality From 1970 to 2014, the USGS and two state agencies (Montana Bureau of Mines and Geology [MBMG] and North Dakota State Water Commission [NDSWC]) collected and analyzed groundwater samples from 7,502 groundwater wells in the Williston Basin for at least 1 of the 5 commonly moni tored constituents. A total of 3,194, 2,505, and 1,803 wells completed in the Quaternary unconsolidated, lower Tertiary, and Upper Cretaceous aquifer systems, respectively, were sampled for at least 1 of the 5 constituents (Boughton and others, 2022, table 3-5). Most of these wells were sampled only once during this period; however, some were sampled as many as 92 times, but not for all five constituents. A list of the aquifers sampled by aquifer system, and information on the location and depth of each well are provided in the associated data release (Boughton and others, 2022, tables 3-4, 3-5). Summary statistics by well for each of the five commonly monitored constituents are provided in tables 3-8 to 3-12 of the data release (Boughton and others, 2022). The range and statistical distribution of these constituents are shown using boxplots (fig. 27). The spatial distribution of wells sampled and range in measurements or concentrations (Boughton and others, 2022) for the five commonly monitored constituents are shown in figures 28 to 32. Wells completed in the Quaternary unconsolidated aquifer system are distributed throughout the study area, but well density is greater in the northeastern part of the Williston Basin. This is likely due to more glacial aquifer material being present in this area in comparison to other areas. The fewest wells completed in the Quaternary unconsolidated aquifer system are in the south central and southwestern parts of the Williston Basin, again likely because of less glacial and alluvial material present in these areas (fig. 1). Wells completed in the lower Tertiary aquifer system are reasonably distributed in the Williston Basin, except for the northeastern and southern parts of the area. Wells com pleted in the Upper Cretaceous aquifer system are not as well distributed in comparison to the other aquifer systems. Within the Williston Basin, there are no wells present in the north ern and eastern parts of North Dakota and the eastern part of South Dakota. There may be multiple reasons for wells to be sampled more frequently in specific areas for certain aqui fer units. Regardless, this information may be beneficial in designing future water-quality monitoring programs because it helps to identify gaps in spatial coverage by aquifer system and in analytical results for specific constituents. In addition, the data may provide a basis for future comparisons of mea surements or concentrations. Specific conductance measured in groundwater samples from 5,059 wells collected from 1970 to 2014 were sum marized for each well. Specific conductance and median specific conductance (for wells with more than one measure ment) range from 2.9 to 807,299 µS/cm for the Quaternary unconsolidated aquifer system, 153 to 49,001 µS/cm for the lower Tertiary aquifer system, and 180 to 15,000 µS/cm for the Upper Cretaceous aquifer system (figs. 27A, 28; Boughton and others, 2022, table 3-8). Although the data are publicly available, the minimum specific conductance values may not be representative of environmental conditions. Among the three aquifer systems, specific conductance varies the most in waters from the Quaternary unconsolidated aquifer system (Boughton and others, 2022, table 3-8). In general, the range in specific conductance tends to be smaller in waters from the Upper Cretaceous aquifer system. Specific conductance tends to be more variable in waters from the lower Tertiary and Qua ternary unconsolidated aquifer systems (fig. 27A). TDS was measured in groundwater samples from 5,831 wells in the Williston Basin (Boughton and others, 2022, table 3-9), but concentrations are only summarized for 5,545 wells in which TDS was measured above detection levels (figs. 27B, 29). TDS concentrations and median TDS concen trations (for wells with more than one measurement) range from 103 to 39,200 µS/cm for the Quaternary unconsolidated aquifer system, 79 to 29,198 µS/cm for the lower Tertiary aquifer system, and 142 to 7,720 µS/cm for the Upper Cre taceous aquifer system (figs. 27B, 29; Boughton and others, 2022, table 3-9).
54 Potential Effects of Energy Development, Williston Basin—Water Resources Table 8. Summary of trace metals measured in groundwater samples from the Williston Basin, from 1993 to 2014. [EPA, U.S. Environmental Protection Agency; MCL, maximum contaminant level; AL, action level; SMCL, secondary maximum contaminant level; --, not available] Trace metal Number of wells by analysis fraction type List of analytical censoring levels for dissolved trace metals, in micrograms per liter Total number of dissolved analyses Summary statistics for detected concentration in dissolved fraction, in micrograms per liter Number of nondetections EPA (2009, 2012) levels,1 in micrograms per liter Dissolved Total Minimum Mean Maximum Number of dissolved analyses with values reported as detections MCL or AL SMCL Quaternary unconsolidated Aluminum 1.6, 1.7, 3.4, 11, 15, 30, 50 50-200 Arsenic 0.022, 0.03, 0.12, 1, 5 Barium 0.07, 0.2 2,000 Chromium 0.06, 0.12, 0.35, 1, 2, 5, 10 Copper 0.4, 0.5, 0.8, 1, 2, 5, 10 1,300 1,000 Iron 3, 3.2, 5, 6, 10, 50 1,405 9,600 Lead 0.015, 0.03, 0.08, 0.125, 1, 2, 5, 100 Selenium 0.03, 0.08, 0.15, 1, 5 Strontium 7,200 Zinc 0.6, 1.4, 2, 2.8, 5, 7, 10 5,000 Lower Tertiary Aluminum 30, 50 50-200 Arsenic 1, 5 Barium 1, 5 2,000 Chromium 1, 5, 10 1,430 Copper 3, 50 1,300 1,000 Iron 5,270 Lead 1, 2, 5, 10, 100 Selenium 1, 5 Strontium 1,479 9,621 Zinc 2, 5, 10 5,000
Quality of Water Resources 55 Table 8. Summary of selected trace metal data in the Williston Basin at groundwater sites with samples analyzed during 1993 through 2014.—Continued [EPA, U.S. Environmental Protection Agency; MCL, maximum contaminant level; AL, action level; SMCL, secondary maximum contaminant level; --, not available] Trace metal Number of wells by analysis fraction type List of analytical censoring levels for dissolved trace metals, in micrograms per liter Total number of dissolved analyses Summary statistics for detected concentration in dissolved fraction, in micrograms per liter Number of nondetections EPA (2009, 2012) levels,1 in micrograms per liter Dissolved Total Minimum Mean Maximum Number of dissolved analyses with values reported as detections MCL or AL SMCL Upper Cretaceous Aluminum 1.6, 30, 50 50-200 Arsenic2 0.12, 1, 5 Barium 3,300 2,000 Chromium 1, 2, 5, 6, 10 Copper 0.4, 0.8, 2, 5, 10 1,300 1,000 Iron 3, 5, 6, 10, 50 5,600 Lead 0.08, 0.16, 1, 2, 5, 100 Selenium 0.08, 0.16, 1, 5 Strontium 2,900 Zinc 0.6, 2, 5, 10 5,000 1A MCL is the maximum permissible level of a contaminant in water delivered to users of a public-water system and is a health-based enforceable regulation. SMCLs are nonenforceable guidelines regarding cosmetic or aesthetic effects of drinking water. An AL is the concentration of copper or lead in drinking water at or above which additional steps are required to reduce the constituent concentration (EPA, 2009, 2012). For regulatory purposes, the AL is applied only to tap water samples, and only if more than 10 percent of the samples exceeded the AL. 2 One large arsenic detection (973 micrograms per liter) in Boughton and others (2022, table 3-15) was removed for calculation of summary statistics. This value is anomalously large in comparison to all other arsenic concentrations measured in the Upper Cretaceous aquifer system (0.46-26.9 micrograms per liter; this table if this value is not used to calculate summary statistics), and the value is much greater than the one other detection (1 microgram per liter) in the same well. Retention of the larger value would result in a larger calculated mean (44.9 micrograms per liter) and maximum detected concentration (973 micrograms per liter).
56 Potential Effects of Energy Development, Williston Basin—Water Resources Table 9. Summary of selected trace metal data in the Williston Basin at stream and river sites that had 10 or more samples collected during 1993 through 2014. [EPA, U.S. Environmental Protection Agency; MCL, maximum contaminant level; AL, action level; SMCL, secondary maximum contaminant level; --, not available] Trace metal Number of sites by analysis fraction type List of analytical censoring levels for dissolved trace metals, in micrograms per liter Total number of dissolved analyses Summary statistics for detected concentration in dissolved fraction, in micrograms per liter Number of nondetections EPA (2009, 2012) levels,1 in micrograms per liter Dissolved Total Minimum Mean Maximum Number of dissolved analyses with values reported as detections MCL or AL SMCL Aluminum 0.009, 0.01, 1, 1.6, 1.7, 2, 3, 3.4, 4, 6.6, 8, 10, 11, 17, 20, 50 1,345 25,982 50-200 Arsenic 0.022, 0.03, 0.044, 0.06, 0.12, 0.18, 0.2, 0.26, 0.9, 1, 2, 5 2,173 1,688 Barium 0.05, 0.07, 0.08, 0.14, 0.2, 0.4, 1, 100 1,418 1,400 2,000 Chromium 0.8, 1, 2, 5, 10 1,130 Copper 0.23, 0.4, 0.5, 1, 1.3, 2.4, 5, 10 1,255 1,300 1,000 Iron 0.007, 0.01, 0.05, 3, 3.2, 4, 6, 6.4, 7, 8, 9.6, 10, 16, 18, 19.2, 24, 30, 50 2,527 28,900 1,860 Lead 0.015, 0.03, 0.045, 0.06, 0.075, 0.08, 0.12, 0.15, 0.16, 0.2, 0.24, 1, 2, 5, 9, 10, 100 2,037 1,917 Selenium 0.03, 0.04, 0.06, 0.08, 0.2, 0.3, 0.33, 0.4, 0.5, 0.7, 1, 2, 5 2,234 1,287 Strontium 0.08, 0.2, 0.4 1,147 2,300 1,147 Zinc 0.2, 0.6, 1, 1.2, 1.4, 1.8, 2, 2.8, 3, 4, 4.2, 5, 5.6, 9, 10, 14, 20 1,192 5,000 1A MCL is the maximum permissible level of a contaminant in water delivered to users of a public-water system and is a health-based enforceable regulation. SMCLs are nonenforceable guidelines regarding cosmetic or aesthetic effects of drinking water. An AL is the concentration of copper or lead in drinking water at or above which additional steps are required to reduce the constituent concentration (EPA, 2009, 2012). For regulatory purposes, the AL is applied only to tap water samples, and only if more than 10 percent of the samples exceeded the AL.
Quality of Water Resources 57 Table 10. Summary of selected trace metal data in the Williston Basin at lake sites with samples analyzed during 1993 through 2014. [EPA, U.S. Environmental Protection Agency; MCL, maximum contaminant level; AL, action level; SMCL, secondary maximum contaminant level; --, not available] Trace metal Number of sites by analysis fraction type List of analytical censoring levels for dissolved trace metals, in micrograms per liter Total number of dissolved analyses Summary statistics for detected concentration in dissolved fraction, in micrograms per liter Number of nondetections EPA (2009, 2012) levels,1 in micrograms per liter Dissolved Total Minimum Mean Maximum Number of dissolved analyses with values reported as detections MCL or AL SMCL Aluminum 1, 1.6, 1.7, 3.2, 3.4, 10, 10.2, 50 6,820 50-200 Arsenic 0.022, 0.044, 0.06, 0.12, 0.2, 0.6, 1, 1.8 Barium 0.07, 0.08, 0.14, 0.2, 0.4, 1, 3, 47 2,000 Chromium 0.06, 0.12, 0.2, 0.36, 0.8, 0.9, 1, 1.2, 2, 10 Copper 0.23, 0.4, 0.5, 1, 3, 5, 10 1,300 1,000 Iron 3, 3.2, 4, 4, 6, 6, 6.4, 6.4, 7, 8, 8, 9, 10, 10, 12, 16, 18, 30, 260 7,220 Lead 0.015, 0.03, 0.08, 0.09, 0.12, 0.2, 0.36, 0.8, 1, 2, 100 Selenium 0.03, 0.04, 0.08, 0.2, 1, 2 Strontium 0.2, 0.4, 1 Zinc 0.2, 0.6, 1, 1.4, 1.8, 2, 2.8, 6, 8.4, 9, 10, 30 5,000 1A MCL is the maximum permissible level of a contaminant in water delivered to users of a public-water system and is a health-based enforceable regulation. SMCLs are nonenforceable guidelines regarding cosmetic or aesthetic effects of drinking water. An AL is the concentration of copper or lead in drinking water at or above which additional steps are required to reduce the constituent concentration (EPA, 2009, 2012). For regulatory purposes, the AL is applied only to tap water samples, and only if more than 10 percent of the samples exceeded the AL.
58 Potential Effects of Energy Development, Williston Basin—Water Resources 1,868 1,553 1,315 1,818 1,537 1,067 D. Sulfate concentration for water years 1970-2014 Sulfate, in milligrams per liter C. pH for water years 1970-2014 pH, in standard units A. Specific conductance for water years 1970-2014 Specific conductance, in microsiemens per centimeter at 25 degrees Celsius E. Chloride concentration for water years 1970-2014 B. Total dissolved-solids concentration for water years 1970-2014 Total dissolved-solids concentration, in milligrams per liter 1,000 10,000 100,000 1,000,000 1,000 10,000 100,000 1,000 10,000 100,000 1,000 10,000 100,000 Secondary maximum contaminant level Secondary maximum contaminant level Lower secondary maximum contaminant level Upper secondary maximum contaminant level Secondary maximum contaminant level Lower Tertiary Quaternary unconsolidated Upper Cretaceous Lower Tertiary Quaternary unconsolidated Upper Cretaceous 2,085 1,528 1,446 1,730 2,745 1,070 1,864 1,523 1,337 1,000,000 10,000,000 EXPLANATION Chloride, in milligrams per liter [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Number of wells Largest value within 1.5 times interquartile range above 75th percentile 75th percentile Median 25th percentile Smallest value within 1.5 times the interquartile range below 25th percentile Far-out value—Value is times the interquartile range beyond either end of box Outside value—Value is >1.5 and times the interquartile range beyond either end of the box Interquartile range Figure 27. Range and statistical distribution of A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved-solids concentrations, in milligrams per liter; C, pH, in standard units; D, sulfate concentrations, in milligrams per liter; and E, chloride concentrations, in milligrams per liter measured in groundwater samples from the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014. A median value was calculated and plotted for wells with more than one sample.
Quality of Water Resources 59 100° 105° 110° 48° 45° ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! !! !! !! ! ! ! ! ! !!! ! ! !! ! ! !! ! ! ! ! ! ! ! ! !!! ! ! !! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !!! !! ! ! !! !! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! !! !! ! !! ! ! !! ! !!! ! !! ! ! !! !! ! !!! ! !!! ! ! ! ! ! !!! !! !! ! ! ! !! ! ! ! ! !! ! ! ! !!! !! !!! ! ! !! !! ! ! ! ! ! !! !! ! ! ! !! ! !!! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! !! !! !! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! !!! !!! ! !!! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! ! ! ! ! !!! ! ! !!! ! ! ! ! ! !! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! !! !! ! ! ! !! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! !! !!! !! ! ! ! ! ! ! !! !! !! !! !! !! ! ! !! ! ! !! !! ! !!! ! ! ! ! !!! ! ! !! !! !! !! ! ! ! ! ! !!! ! ! ! ! ! !! !! ! ! !!! ! ! ! ! ! !! !! ! !! !! !! ! !!! ! ! ! ! ! !! !! ! ! ! ! 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!! ! ! ! !!! ! ! !! ! !!! ! !! ! ! ! !! !!! ! ! !! ! !!! !! !! !! ! ! ! ! ! ! ! !!! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! !! ! !! !! !! !!! ! ! ! ! ! ! ! ! !!! ! !! !!! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! !! ! !!! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! !! !! ! ! ! ! ! !! ! !! ! ! ! !!! ! !! ! !! !! !! !! ! !! !! ! ! ! ! !!! !! ! !! ! !! ! !! !! ! !! ! !! ! ! ! !!! ! ! ! !! ! ! ! ! ! ! ! ! !!! ! ! !! ! ! !! ! ! ! !! ! ! ! ! !! ! ! ! ! !! !! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! !! !! ! ! !! !! ! ! !! ! ! ! ! !! ! !!! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! !! ! !! ! ! ! ! ! !! !! !! ! !! !!! ! ! ! ! !! ! !! ! !! ! ! !!! ! ! !! ! ! ! ! !!! ! ! ! !! ! ! ! ! ! ! !! ! ! ! !! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! !!! !! ! ! ! ! ! ! ! !! ! ! !!! ! ! 100° 105° 110° ! ! !! ! !!! ! ! ! ! !! !! !! !! ! ! !! ! ! ! !! !! ! ! ! ! ! !! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! !! ! ! ! !!! ! ! ! ! ! !! ! ! !! !! ! ! !! ! !! ! ! ! ! !! !! !!! ! !!! ! !! ! ! !!! ! ! ! ! ! !! ! !!! ! ! !! ! ! ! ! !! ! ! ! !!! ! ! ! ! !! !! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! !! ! !! !! ! ! ! !!! ! ! ! !!! ! !! !! ! ! !!! ! !!! ! ! !! !!! !! ! ! ! ! ! ! !! !! !! !! ! ! ! ! ! ! !! ! !! ! !! ! !! ! ! ! ! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! !! !! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! !! ! ! !! !! ! !!! ! ! !! !! !!! ! !! !! ! !! ! !! !! ! ! ! ! !! !! ! !! !! ! ! !! ! ! ! ! ! ! !!! !! ! ! !! !! !! !! !!! ! ! !!! !! !! ! ! ! ! !!! !! ! ! ! !! ! ! ! ! !! ! !!! ! ! ! ! ! ! !! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! !!! ! ! !! ! !!! ! ! !! ! ! ! ! ! !! ! ! !! !! ! !!! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! !!! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! !!! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! !!! ! ! !!! ! !! ! !!! ! ! !!! ! !! ! ! ! !! !! !!! ! ! ! ! ! ! ! ! ! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! !!! !! ! ! !!! !!! ! ! !! ! !! ! ! !! !! ! ! ! ! !!! ! !!! ! ! !! ! ! ! !! !!! ! ! ! ! ! ! !! ! ! !!! !! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! !!! ! ! !! ! !! !! ! ! !! !! !! !! ! !! !! ! ! ! ! ! ! ! !!! !! ! ! !! ! ! ! ! ! ! !! !! ! ! ! !! ! ! ! ! ! !! ! ! ! ! !! ! !! !! ! ! ! ! ! ! ! !!! !! !! !! ! !! ! !!! !! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! !! !! !! ! !! !! ! ! ! !! !! !! ! !! !! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! !! ! ! ! ! !! !! ! ! ! ! ! ! ! !! ! !! ! !! !!! ! ! ! ! ! ! ! ! ! ! !! !!! ! ! ! ! !! ! ! ! !!! ! ! ! ! !!! !! ! !!! !! ! ! !! !! !! !!! ! ! ! !! ! !! !! !! !!! !! ! ! ! ! ! !! ! ! !! ! ! !! ! ! ! ! !! ! !! !! ! !!! ! ! !! ! ! !! !! !!! !! !! ! ! !!! !! ! ! ! ! ! ! !! ! ! ! !! ! !! ! ! ! ! !! ! ! !!! !! !! ! !!! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! !! ! ! !! ! !!! !! !!! !! !! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !!! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! !! !! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! !! !! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! 48° 45° ! ! ! !! ! ! ! ! ! ! !! ! !! !! ! ! ! ! ! !! ! ! ! !! ! !!! !! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !!! !! !! ! ! ! ! ! ! !!! !! ! ! !! ! !! !! ! !! ! !! ! ! ! !!! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! !! ! !!! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! !! ! !! ! ! !! !!! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! !! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !!! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !!! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! !! ! !! ! ! ! ! !! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! !! ! ! ! !! !! ! !! ! ! ! ! !! ! ! ! ! ! !! ! ! !! ! !!! ! !!! !! ! ! ! ! ! !! !! ! ! ! ! !! !! ! ! ! ! !! ! ! !! ! !! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! !! ! ! ! ! !! !! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! !!! ! !! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! !!! ! ! ! !! ! ! ! ! ! ! ! !!! ! !! ! ! !! ! !! !! ! ! ! ! !!! ! ! !! ! ! ! !!! ! ! ! ! !! !! ! ! ! !!! !!! ! ! ! !! ! !!! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! !! ! ! ! ! ! !! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! !! !! ! ! ! ! ! ! !! ! ! !! ! ! ! !! ! !! !! ! ! ! ! ! !!! ! ! ! ! ! !! !! ! ! ! ! ! !! ! !!! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! !! ! ! ! ! !!! ! MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES Chloride concentration and median chloride concentration (for wells with more than one measurement), in milligrams per liter 0 to 250 251 to 500 501 to 1,000 1,001 to 5,000 5,001 to 10,000 10,001 to 40,000 40,001 to 81,000 Base map modified from U.S. Geological Survey, Esri, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 Williston Basin boundary Bakken Formation boundary Upper Fort Union aquifer Middle Fort Union hydrogeologic unit Lower Fort Union aquifer Upper Hell Creek hydrogeologic unit Lower Hell Creek aquifer Hydrogeologic unit EXPLANATION Upper Cretaceous Lower Tertiary Quaternary unconsolidated MILES KILOMETERS Lower Tertiary aquifer system Upper Cretaceous aquifer system Quaternary unconsolidated aquifer system Figure 32. Chloride concentrations and median chloride concentrations (for wells with more than one measurement) measured in groundwater samples from wells in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 through 2014.
64 Potential Effects of Energy Development, Williston Basin—Water Resources Values for pH measured in groundwater samples from 4,724 wells in the Williston Basin collected from 1970 to 2014 were summarized for each well. The pH and median pH (for wells with more than one measurement) range from 3.4 to 10.6 standard units for the Quaternary unconsolidated aquifer system, 1.6 to 13.3 standard units for the lower Tertiary aqui fer system, and 6.0 to 10.3 standard units for the Upper Cre taceous aquifer system (figs. 27C, 30; Boughton and others, 2022, table 3-10). Although the data are publicly available, the minimum and maximum pH values may not be representative of environmental conditions. In general, pH measurements tend to be smaller in the Quaternary unconsolidated aquifer system and larger in the Upper Cretaceous aquifer system (fig. 27C). Sulfate was measured in groundwater samples from 4,774 wells in the Williston Basin (Boughton and others, 2022, table 3-11), but concentrations are only summarized for 4,736 wells with sample concentrations that were above detection levels (figs. 27D, 31). Sulfate concentrations and median sulfate concentrations (for wells with more than one measurement) range from 0.1 to 35,418 mg/L in the Quater nary unconsolidated aquifer system, 0.1 to 16,000 mg/L in the lower Tertiary aquifer system, and 0.2 to 3,480 mg/L in the Upper Cretaceous aquifer system (figs. 27D, 31). Although the data are publicly available, the minimum sulfate values may not be representative of environmental conditions. In general, sulfate concentrations tend to be smaller in the Upper Creta ceous aquifer system and larger in the lower Tertiary aquifer system. Chloride was measured in groundwater samples from 4,910 wells in the Williston Basin (Boughton and others, 2022, table 3-12), but concentrations are only summarized for 4,422 wells with sample concentrations that were above detection levels (figs. 27E, 32). Chloride concentrations and median chloride concentrations (for wells with more than one measurement) range from 0.1 to 81,000 mg/L in the Quater nary unconsolidated aquifer system, 0.1 to 23,300 mg/L in the lower Tertiary aquifer system, and 0.1 to 4,300 mg/L in the Upper Cretaceous aquifer system (figs. 27E, 32). Although the data are publicly available, the minimum chloride values may not be representative of environmental conditions. In general, chloride concentrations are smaller in the lower Tertiary aqui fer system and larger in the Upper Cretaceous aquifer system, although some of the largest concentrations were from wells completed in the Quaternary unconsolidated aquifer system (figs. 27E, 32). By aquifer system, the total number of wells with samples analyzed for dissolved trace metals ranges from 83 to 156. The number of wells with sample analytical results was dependent on the trace metal (table 8); for example, aluminum was measured in samples from 83 wells, whereas iron was measured in samples from 156 wells (table 8; Boughton and others, 2022, tables 3-13 to 3-15). In general, more samples from wells completed in the Quaternary unconsolidated aquifer system were analyzed for any 1 of the 10 trace metals (580) as compared to those completed in the lower Tertiary (217) or Upper Cretaceous (236) aquifer systems (Boughton and others, 2022, tables 3-13 to 3-15, respectively). Censor ing levels for dissolved trace metal analyses varied consid erably, and many analyses had unknown censoring levels. Summary statistics were computed only for detected trace metal concentrations in the dissolved fraction measured in micrograms per liter. Mean concentrations from wells com pleted in the Quaternary unconsolidated aquifer system were less than EPA MCLs, SMCLs, or ALs (EPA, 2009, 2012) except for arsenic, iron, and lead with mean concentrations of 10.2 micrograms per liter (µg/L) (MCL=10 µg/L), 1,405 µg/L (SMCL=300 µg/L), and 21.3 µg/L (AL=15 µg/L), respectively (table 8). Mean dissolved trace metal concentrations from wells completed in the lower Tertiary aquifer system were less than or equal to EPA MCLs, SMCLs, or ALs except for iron, with a mean concentration of 592 µg/L (SMCL=300 µg/L; table 8). Mean dissolved trace metal concentrations from wells completed in the Upper Cretaceous aquifer system were less than EPA MCLs, SMCLs, or ALs except for aluminum and iron with mean concentrations of 235 µg/L (SMCL range=50- 200 µg/L) and 382 µg/L (SMCL=300 µg/L), respectively (table 8). Water Quality of Streams and Rivers At least 1 of the 5 commonly monitored constituents was monitored at 329 sites along streams and rivers in the Williston Basin from 1970 to 2014 (Boughton and others, 2022, table 3-6). Most sampling sites for streams and rivers in the Williston Basin are in North Dakota (211 of 329 sites; 64 percent). Water-quality samples for streams and rivers were collected by six State agencies (North Dakota Department of Health [NDDH], NDSWC, Montana Department of Envi ronmental Quality [MDEQ], SDDENR, MBMG, and South Dakota Geological Survey), the Native American Tribes with land holdings in the Williston Basin area (Assiniboine and Sioux Tribes of the Fort Peck Indian Reservation, Three Affili ated Tribes [Mandan, Hidatsa, and Arikara Nation] of the Fort Berthold Indian Reservation, and Turtle Mountain Band of Chippewa Indians of North Dakota), and four Federal agencies (USACE, EPA, USGS, and National Park Service) (Boughton and others, 2022, table 3-6).
Quality of Water Resources 65 The number of stream water-quality samples collected and analyzed for specific conductance at sites in the Willis ton Basin from 1970 to 2014 is presented in figure 33 and in table 3-16 of the data release (Boughton and others, 2022). Specific conductance was selected from among the five com monly monitored constituents because it was measured in the greatest number of samples and represents the spatial distribu tion of sampling sites within the Williston Basin. The spatial distribution of surface-water sites sampled for specific con ductance was compared with the number of oil and gas wells in the HUC-8 watersheds in the Williston Basin (fig. 33). Overall, the areas with the greatest number of specific con ductance samples collected from streams and rivers are not collocated with the areas where the most intensive energy development was present; for example, the Lake Sakakawea HUC-8 (10110101) has the greatest number of oil and gas wells (10,667), but this area has fewer numbers of samples by site in comparison to many other watersheds. The Lower Yellowstone HUC-8 (10100004) has the second most oil and gas wells (3,170) and has fewer samples collected in compari son to many other watersheds. The Yellowstone River near Sidney, Mont. (streamgage 06329500; fig. 17), however, is in the Lower Yellowstone HUC-8 (10100004) and had the third greatest number of samples collected for the period of record (Boughton and others, 2022, table 3-16). Many of the sites with the greatest numbers of samples are in the eastern part of the Williston Basin, in areas that have the least number of oil and gas wells (for example, Lower Heart HUC-8 [10130203]; fig. 33). Areas of the Williston Basin where there is a lack of stream water-quality sampling sites as indicated by the collection of specific conductance samples can be visualized in figure 34, which illustrates minimum, median, and maxi mum specific conductance values for each site from 1970 to 2014. These underrepresented areas may be targeted for future water-quality sampling programs. The concentrations of the five commonly monitored con stituents are graphically summarized for the Williston Basin (fig. 35) and for one site (fig. 36), the Yellowstone River near Sidney, Mont, (streamgage 06329500; fig. 17). This USGS streamgage was selected because of the sample collection intensity for the period of record, it has substantial streamflow data, it is in the Lower Yellowstone HUC-8 (10100004), and it has the second greatest number of oil and gas wells per HUC-8 (fig. 33). Summary statistics are presented in Bough ton and others (2022, tables 3-16 to 3-20). Specific conductance was measured at stream waterquality sampling sites in the Williston Basin from 1970 to 2014, and values ranged from 1.08 to 13,300 μS/cm (fig. 35A; Boughton and others, 2022, table 3-16). In general, median specific conductance values were greater in the western part than in the eastern part of the basin (fig. 34B). Median specific conductance values for all sites ranged from 800 to 2,000 μS/cm (fig. 35A). From 2003 to 2012, a few question able measurements that could not be verified were reported as less than 10 μS/cm from smaller tributaries Hell Creek, Horse Creek, Buffalo Springs, and East Redwater River near Circle, Mont. The largest specific conductance (13,300 μS/cm) mea sured was at streamgage 06177520 (Horse Creek near Circle, Mont.; Boughton and others, 2022, table 3-16). The specific conductance values for streamgage 06329500 were much less variable and ranged from 450 to 850 μS/cm from 1970 to 2014 (Boughton and others, 2022, table 3-16). Total dissolved solids were measured at 236 sites in the Williston Basin, and values ranged widely from 10 to 19,100 mg/L (Boughton and others, 2022, table 3-17). Although the data are publicly available, the minimum TDS values may not be representative of environmental conditions. Median TDS values generally were greater in the western part of the basin (fig. 37). The median TDS values for all sites and years were between 500 and 1,500 mg/L (fig. 35B). Median TDS values exceeded the EPA SMCL of 500 mg/L (EPA, 2009, 2012) at 216 of 236 sites (91 percent) sampled from 2008 to 2014. Annual median TDS values for streamgage 06329500 were between 350 and 600 mg/L from 1970 to 2014 (fig. 36B). Very few TDS samples were collected at this site after about 2002. Values for pH were measured in samples from 275 sites in the Williston Basin, and values ranged widely from 1.78 to 13.14 standard units (Boughton and others, 2022, table 3-18). Although the data are publicly available, the minimum and maximum pH values may not be representative of envi ronmental conditions. Median pH values measured at each site generally were within the EPA SMCL range of 6.5 to 8.5 standard units, but median pH values measured at 50 of 275 sites (18 percent) were greater than the upper EPA SMCL of 8.5 standard units (Boughton and others, 2022, table 3-18). Maximum pH values were greater than 8.5 standard units in samples from 84 percent of the sites. Minimum pH values were less than the lower EPA SMCL of 6.5 standard units at 27 of 275 sites (Boughton and others, 2022, table 3-18). In general, median pH values for all years and sites were between 7.5 and 8.5 standard units (fig. 35C). A few pH values that were less than 4 standard units (fig. 38) likely were not reviewed before entry into the WQP. The annual median pH values for Yellowstone River near Sidney, Mont. (USGS streamgage 06329500) also were between 7.5 and 8.5 standard units from 1970 to 2014 (fig. 36C).
66 Potential Effects of Energy Development, Williston Basin—Water Resources 95° 100° 105° 110° 48° 45° MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES CANADA MILES KILOMETERS Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 10 to 25 26 to 50 51 to 100 101 to 250 251 to 500 501 to 790 Number of specific conductance samples per site 0 to 100 101 to 500 501 to 3,000 3,001 to 6,000 6,001 to 10,667 Number of oil and gas wells per Hydrologic Unit Code-8 (HUC) boundary—HUC-8 number shown in white Williston Basin boundary Bakken Formation boundary EXPLANATION
Figure 33. Spatial distribution of specific conductance samples from streams and rivers and numbers of oil and gas wells in HUC-8 watersheds in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014.
Quality of Water Resources 67 EXPLANATION 100° 105° 110° 48° 45° !!! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! !! ! ! ! ! !!! ! ! !!! ! ! ! ! !! !!! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! !!! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! !! ! ! !! ! 100° 105° 110° !! ! ! !!! ! ! !! ! ! ! ! !! !! ! !! ! ! !! ! ! !!! ! ! ! ! ! ! ! !! ! !! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! !!! ! ! !! ! ! ! ! !! ! ! ! !! ! ! ! !! ! !! ! ! !!! !!! ! !! ! !! !! ! ! ! ! ! ! ! ! !!! ! !! ! !!! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! !! ! ! ! !! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! 48° 45° !! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! !!! !! ! ! !! ! ! ! ! ! ! ! ! !! ! !!! ! ! ! !!! ! ! ! ! ! ! !! ! ! ! ! ! ! !! !! ! !! ! !!! ! ! !!! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! !!! ! !! ! ! !! ! ! ! !! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Maximum MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Median MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Minimum ! 0 to 500 ! 501 to 1,000 ! 1,001 to 2,000 ! 2,001 to 4,000 ! 4,001 to 7,000 ! 7,001 to 10,000 ! 10,001 to 13,300 Specific conductance, in microsiemens per centimeter at 25 degrees Celsius Williston Basin boundary Bakken Formation boundary Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 MILES KILOMETERS Figure 34. Specific conductance in streams and rivers in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014.
68 Potential Effects of Energy Development, Williston Basin—Water Resources 1,472 1,570 1,200 1,240 A. Specific conductance for water years 1970-2014 Specific conductance, in microsiemens per centimeter at 25 degrees Celsius B. Total dissolved-solids concentration for water years 1970-2014 1,000 10,000 100,000 1,000 10,000 100,000 Total dissolved-solids concentration, in milligrams per liter Water year Secondary maximum contaminant level EXPLANATION Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Figure 35. Annual variability in values of constituents for all streams and rivers in the Williston Basin, from 1970 to 2014. A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter.
Quality of Water Resources 69 Water year Water year 1,000 10,000 D. Sulfate concentration for water years 1970-2014 Secondary maximum contaminant level Sulfate, in milligrams per liter as sulfate 1,045 1,146 pH, in standard units C. pH for water years 1970-2014 Lower secondary maximum contaminant level Upper secondary maximum contaminant level EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside Figure 35. Annual variability in values of constituents for all streams and rivers in the Williston Basin, from 1970 to 2014. A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter.—Continued
70 Potential Effects of Energy Development, Williston Basin—Water Resources Chloride, in milligrams per liter as chloride 1,000 E. Chloride concentration for water years 1970-2014 Water year Secondary maximum contaminant level Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Figure 35. Annual variability in values of constituents for all streams and rivers in the Williston Basin, from 1970 to 2014. A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter.—Continued
Quality of Water Resources 71 A. Specific conductance for water years 1970-2014 Specific conductance, in microsiemens per centimeter at 25 degrees Celsius 1,000 2,000 Water year Water year 1,000 2,000 B. Total dissolved-solids concentration for water years 1970-2014 Total dissolved-solids concentration, in milligrams per liter Secondary maximum contaminant level EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside Figure 36. Annual variability in values of constituents for the Yellowstone River near Sidney, Montana (streamgage 06329500), from 1970 to 2014. A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter.
72 Potential Effects of Energy Development, Williston Basin—Water Resources Lower secondary maximum contaminant level Upper secondary maximum contaminant level Secondary maximum contaminant level Water year D. Sulfate concentration for water years 1970-2014 C. pH for water years 1970-2014 Sulfate, in milligrams per liter as sulfate pH, in standard units EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside Figure 36. Annual variability in values of constituents for the Yellowstone River near Sidney, Montana (streamgage 06329500), from 1970 to 2014. A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter.—Continued
Quality of Water Resources 73 E. Chloride concentration for water years 1970-2014 Water year Chloride, in milligrams per liter as chloride EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside Figure 36. Annual variability in values of constituents for the Yellowstone River near Sidney, Montana (streamgage 06329500), from 1970 to 2014. A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter.—Continued
74 Potential Effects of Energy Development, Williston Basin—Water Resources 100° 105° 110° 48° 45° ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! ! ! ! ! ! ! ! !!! ! ! ! ! !!! ! !! !! ! !! ! ! ! ! ! ! !! ! !! ! ! !! ! !!! ! ! ! !!! !! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! !! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! !! !! ! !! ! 100° 105° 110° ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! !!! ! ! !! ! ! !! ! !! !!! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! !! !! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! !! ! !! ! ! ! ! !! ! ! ! ! !! ! !! !! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! 48° 45° ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! !! !! ! !!! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! !! ! ! ! ! !! ! !! ! !! ! ! ! ! ! !!! ! ! !! ! !! !!! ! ! ! ! ! ! ! ! !! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! !! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Maximum MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Median MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Minimum 10 to 500 501 to 1,000 1,001 to 2,000 2,001 to 3,500 3,501 to 5,000 5,001 to 10,000 10,001 to 19,100 Total dissolved-solids concentration, in milligrams per liter EXPLANATION Williston Basin boundary Bakken Formation boundary Base map modified from U.S. Geological Survey, Esri, the Commission for Environmental Cooperation, and the Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 ! ! ! ! ! ! ! MILES KILOMETERS Figure 37. Total dissolved-solids concentrations in streams and rivers in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014. A, minimum; B, median; and C, maximum.
Quality of Water Resources 75 100° 105° 110° 48° 45° ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! !!! ! ! ! !!! ! ! !! ! !!! ! ! ! ! !!! ! !! ! ! ! !! ! ! ! ! ! ! !! ! !! ! ! !! ! ! !! ! ! ! ! !! ! !!! !! !!! ! ! ! ! ! ! ! !! ! ! ! ! !! ! !! ! ! !! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! 100° 105° 110° ! ! ! !!! ! ! !! !! ! !! ! ! ! ! ! ! !! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! !! ! !!! ! ! ! ! ! !! ! ! ! ! ! ! ! !! !! ! !!! ! ! !! ! !!! ! ! ! ! !!! ! !! !! ! ! !! ! ! ! ! ! ! !! ! ! !! ! !! ! ! !! ! !! ! ! !!! ! ! ! ! ! ! !! !!! ! ! ! ! ! ! !! ! ! ! !! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! 48° 45° ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !!! ! ! ! ! !! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! !!! !! ! !! ! ! ! ! !! !! ! !! ! ! ! !! ! !! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !!! ! ! ! ! ! ! ! !! ! !! !!! ! ! ! !! ! !! ! ! ! !! ! ! ! ! !! ! ! !! ! ! !! ! ! !!! !! ! ! ! ! !! ! ! ! ! ! ! !! !!! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Maximum MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Median MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Minimum 1.8 to 4.0 4.1 to 6.0 6.1 to 7.0 7.1 to 8.0 8.1 to 9.0 9.1 to 11.0 11.1 to 13.1 pH, in standard units EXPLANATION Williston Basin boundary Bakken Formation boundary Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 ! ! ! ! ! ! ! MILES KILOMETERS Figure 38. pH in streams and rivers in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014. A, minimum; B, median; and C, maximum.
76 Potential Effects of Energy Development, Williston Basin—Water Resources Sulfate was measured at 188 sites in the Williston Basin, and concentrations ranged from 5 to 7,900 mg/L (Boughton and others, 2022, table 3-19). In general, median sulfate concentrations were greater in the western part of the basin and less in the eastern part of the basin (fig. 39B). Sulfate concentrations also were modeled in a previous study (Gal loway and Vecchia, 2014), and concentrations generally were highest (greater than 750 mg/L) in HUC-8 watersheds in eastern Montana and western North Dakota. Median sulfate concentrations for all sites and years were between 150 and 650 mg/L (fig. 35D). Median sulfate concentrations exceeded the EPA SMCL of 250 mg/L at 147 out of 188 sites (78 percent). Since 1978, about one-half of the median sulfate concentrations exceeded the EPA SMCL of 250 mg/L (EPA, 2009, 2012). Minimum sulfate concentrations reported for 21 of the 188 sites (11 percent) were equal to or greater than the EPA SMCL of 250 mg/L; generally, these samples were collected during storm events (Boughton and others, 2022, table 3-19). The annual median sulfate concentrations for Yel lowstone River near Sidney, Mont. (streamgage 06329500), generally were between 150 and 250 mg/L from 1970 to 2014 (fig. 36D). Chloride was measured at 214 sites in the Williston Basin, and concentrations ranged from 0.1 to 516 mg/L (Boughton and others, 2022, table 3-20). While the maxi mum chloride concentrations at seven sites were greater than 250 mg/L, the median chloride concentrations for all sites in the basin were less than the EPA SMCL (fig. 40B). The median chloride concentrations across all years ranged from 7 to 30 mg/L (fig. 35E). The median chloride concentrations at streamgage 06329500 ranged from 6.5 to 15 mg/L (fig. 36E). Trace metal analyses available for stream and river samples consist of both dissolved and total fractions, but data are presented, and summary statistics are computed, for trace metal concentrations in the dissolved fraction and reported in micrograms per liter (table 9; Boughton and others, 2022, table 3-21). Similarly, samples were analyzed for a wide variety of trace metals, but only information regarding the concentrations of aluminum, arsenic, barium, chromium, cop per, iron, lead, selenium, strontium, and zinc are presented in this section (table 9). Water Quality of Lakes and Reservoirs At least one of the five commonly monitored constituents was included in analyses from 839 lake sites sampled in the Williston Basin from 1970 through 2014 by six State agencies (NDDH, NDSWC, MDEQ, MBMG, SDDENR, and South Dakota Geological Survey), the Native American Tribes with land holdings in the basin (Assiniboine and Sioux Tribes of the Fort Peck Indian Reservations, Three Affiliated Tribes [Man dan, Hidatsa, and Arikara Nation] of the Fort Berthold Indian Reservation, and Turtle Mountain Band of Chippewa Indians of North Dakota), and three Federal agencies (USACE, EPA, and USGS) (Boughton and others, 2022, table 3-7). Figure 41 shows the distribution of lake and reservoir samples analyzed for specific conductance compared to the number of oil and gas wells by HUC-8 watersheds. Because of the importance of Lake Sakakawea for recreation, four sites in the lake were selected to characterize the water quality and compare with data collected from other sites in the Williston Basin (fig. 42). Physical properties such as temperature, dissolved oxygen, pH, and specific conductance had been collected at these four sites since the 1970s. Chemical constituents had been ana lyzed periodically at some of these sites since the 1980s, but consistent data collection for these four sites did not begin until 1993. Data from the WQP and NAWQA project's data compilation for the five commonly monitored constituents were supplemented with data collected from the USACE and NDDH (NDDH, 2015) for these four sites because a complete dataset for these sites was not available from the WQP and the NAWQA project's data compilation. Summary statistics for the five commonly monitored constituents at the selected sites on Lake Sakakawea are available in a data release (Boughton and others, 2022, tables 3-27 to 3-31). Similar to rivers and streams, lakes and reservoirs in the Williston Basin with the greatest number of sites sampled and samples collected are not necessarily near the greatest num ber of oil and gas wells (fig. 41) as evidenced by the spatial distribution of samples for which specific conductance was measured. Specific conductance was one of the five most commonly monitored constituents in lakes and reservoirs, with the largest number and greatest spatial distribution of samples analyzed. The HUC-8 watershed with second highest number of oil and gas wells (10100004; fig. 41) has few sampling sites and typically less than 10 samples collected per site. The HUC-8 watersheds containing the most oil and gas wells gen erally have few lakes and lake sampling sites, and few samples per site; however, the HUC-8 watershed containing Lake Sakakawea (10110101) has 10,667 oil and gas wells, several sampling sites along Lake Sakakawea, and several sites with analytical results from more than 50 samples (fig. 41).
Quality of Water Resources 77 100° 105° 110° 48° 45° ! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! ! ! !!! ! ! !! ! !!! ! ! ! ! !!! ! !! ! ! !! ! ! ! ! ! ! ! ! !! ! !! ! !!! ! ! ! !!! !! ! ! ! ! ! !! ! !! ! ! ! ! !! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! 100° 105° 110° ! ! ! ! ! ! ! !! ! ! !!! ! ! ! !! ! ! ! ! ! ! ! ! !! ! !! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! !! ! !! !!! !! ! ! !!! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! !! ! ! !!! ! !! ! ! ! ! ! ! !! ! !! ! ! ! !! !! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! 48° 45° ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! !! ! ! ! ! ! ! !!! ! !! !! ! !!! !! ! ! ! ! ! !! ! ! !! !! ! ! ! !! ! ! ! ! ! ! !! ! !! ! ! ! ! !! ! !!! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Maximum MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Median MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Minimum 5 to 250 251 to 500 501 to 1,000 1,001 to 2,000 2,001 to 3,500 3,501 to 5,000 5,001 to 7,900 Sulfate concentration, in milligrams per liter EXPLANATION Williston Basin boundary Bakken Formation boundary Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 ! ! ! ! ! ! ! MILES KILOMETERS Figure 39. Sulfate concentrations in streams and rivers in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014. A, minimum; B, median; and C, maximum.
78 Potential Effects of Energy Development, Williston Basin—Water Resources 100° 105° 110° 48° 45° ! ! !! ! ! ! ! ! ! ! ! ! !! !!! !! ! ! !!! ! ! ! !!! ! ! !! ! !!! ! ! ! ! !!! ! !! ! ! !! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! !!! !! ! !! ! !!! ! ! !! ! ! ! ! !! ! !! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! !! ! 100° 105° 110° ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !! ! !!! ! ! ! !!! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! !! ! !!! ! ! !! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! !!! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! 48° 45° ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! !!! !!! ! ! ! ! !!! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! !! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! !! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Maximum MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Median MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Minimum 0.1 to 25 26 to 50 51 to 75 76 to 100 101 to 225 226 to 350 351 to 516 Chloride concentration, in milligrams per liter Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 EXPLANATION Williston Basin boundary Bakken Formation boundary ! ! ! ! ! ! ! MILES KILOMETERS Figure 40. Chloride concentrations in streams and rivers in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014. A, minimum; B, median; and C, maximum.
Quality of Water Resources 79 95° 100° 105° 110° 48° 45° MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES CANADA MILES KILOMETERS Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 1 to 25 26 to 50 51 to 75 76 to 100 101 to 125 126 to 145 Number of specific conductance samples per site 0 to 100 101 to 500 501 to 3,000 3,001 to 6,000 6,001 to 10,667 Number of oil and gas wells per Hydrologic Unit Code-8 (HUC-8) boundary—HUC-8 number shown in white Williston Basin boundary Bakken Formation boundary EXPLANATION Figure 41. Spatial distribution of specific conductance samples from lakes and reservoirs and numbers of oil and gas wells in hydrologic unit code-8 (HUC-8) watersheds in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014.
80 Potential Effects of Energy Development, Williston Basin—Water Resources EXPLANATION !( Water sampling location and identifier Williston Basin boundary Bakken Formation boundary Base map modified from Esri digital data, variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 105° 100° 110° 48° 45° MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA 5 10 15 20 KILOMETERS 20 MILES ! RM1481 RM1445 RM1412 RM1390 RM1481 LAKE SAKAKAWEA Figure 42. Location of select water-quality sites on Lake Sakakawea sampled from 1993 to 2014.
Quality of Water Resources 81 Across the Williston Basin, specific conductance was measured in lake and reservoir samples from 568 sites from 1970 to 2014 (Boughton and others, 2022, table 3-22). Of the 568 lake sites sampled across the area, 453 sites had fewer than 10 samples (Boughton and others, 2022, table 3-22). Specific conductance was spatially variable for all sites across the Williston Basin (fig. 43). Specific conductance ranged from 30 to 116,000 µS/cm (Boughton and others, 2022, table 3-22), which is consistent with other values reported for lakes and wetlands of the Williston Basin (Gorham and others, 1983; Swanson and others, 1988; Euliss and Mushet, 2004; Tangen and others, 2013; figs. 43, 44A). In comparison to other sampling sites in the Williston Basin as a whole, mea sured specific conductance for the four selected sites on Lake Sakakawea was much less variable, ranging from 339 µS/cm in 2006 to 839 µS/cm in 2012 (fig. 45A, Boughton and others, 2022, table 3-27). An area of higher median specific con ductance generally is along the northern border of Montana and North Dakota (fig. 43). A closer inspection of the dataset indicates the high median values in this area are a group of 19 sites that were sampled once in October of 1983 (Boughton and others, 2022, table 3-22). A specific conductance value of 116,000 µS/cm was measured in a sample collected in 1990 (fig. 44A; Boughton and others, 2022, table 3-22). The sample was collected in an area with no oil or gas wells present (figs. 41, 43C), indicating the elevated specific conductance likely was not due to energy development in the immediate area. Two samples collected in 1990 were the highest median and maximum specific conductance values measured in the Williston Basin from 1970 to 2014 (dark red dots in figs. 43B and 43C, respectively). These high specific conductance mea surements are outliers in the boxplots of specific conductance for 1990 (fig. 44A). Even though the range and variability of median spe cific conductance is substantially less in Lake Sakakawea than for the Williston Basin as a whole, temporal and spatial variability is still present and can primarily be attributed to changes in lake elevation and the effects of inflows and evaporation, respectively (figs. 45A, 46). Depending on lake elevation, retention time in Lake Sakakawea ranges from 0.32 year (elevation of 1,775 ft) to 1.54 years (elevation of 1,855 ft; USACE, 2008). Longer retention time of water in the lake results in increased surface-water evaporation from the lake, resulting in elevated TDS and specific conductance. The highest median specific conductance of 757 µS/cm was measured in 2013, and the lowest median specific conductance of 572 µS/cm was measured in 2009 after a 17-ft increase in lake elevation from 2008 to 2009 (figs. 45A, 46). Initially, the increase in lake elevation contributed fresher water, but once a higher elevation was reached, the longer retention time contributed to higher specific conductance values in subse quent years (fig. 45A). The highest median specific conduc tance was measured in 2013, which was associated with a period of higher lake elevation followed by a period with a decrease in lake elevation (fig. 46). Spatially, median specific conductance increases slightly from upstream to downstream in Lake Sakakawea, ranging from 568 µS/cm at the upstream end to 644 µS/cm at the downstream end of the reservoir (sites RM1481 and RM1390, respectively; fig. 47A). The variabil ity of specific conductance at individual sites decreases from upstream to downstream (fig. 47A). Variability in specific conductance is smallest (ranging from 546 to 783 μS/cm) at the most downstream site at RM1390 and largest (ranging from 339 to 839 µS/cm) at the most upstream site at RM1481 (fig. 47A; Boughton and others, 2022, table 3-27). Similar to specific conductance, TDS concentrations varied spatially across the Williston Basin (fig. 48), with the exception of select Lake Sakakawea sites, which had TDS concentrations that were much less variable (fig. 45B) than other sites in the basin. TDS was measured at 510 sites in the Williston Basin from 1970 to 2014, and concentrations ranged from 11 mg/L in 1995 to 84,500 mg/L in 1983 (figs. 44B, 48; Boughton and others, 2022, table 3-23). In contrast, TDS concentrations in Lake Sakakawea ranged from 211 to 736 mg/L from 1993 to 2014 (fig. 45B; Boughton and others, 2022, table 3-28). Of the 510 lake sites sampled across the basin, 384 sites had 10 or fewer samples, and 327 sites had median TDS concentrations that exceeded the EPA SMCL of 500 mg/L (EPA, 2009, 2012; Boughton and others, 2022, table 3-23). Similar to specific conductance, high median TDS concentrations were observed along the northern border of Montana and North Dakota (fig. 48). Consistent with specific conductance, high TDS concentrations were measured in sam ples collected at sites in the Williston Basin in 1983 (fig. 44B). Within Lake Sakakawea, the same general spatial pat terns observed for specific conductance values were observed for TDS concentrations (fig. 45B). The highest median TDS concentration of 646 mg/L was measured in 2013, and the lowest median specific conductance of 346 mg/L was mea sured in 2010 (fig. 45B). Generally, before 2010 TDS concen trations did not exceed the 500 mg/L EPA SMCL. Beginning in 2012, median TDS concentrations exceeded the 500 mg/L EPA SMCL. Spatially, median TDS concentrations increase from upstream at RM1481 (364 mg/L) to downstream at RM1390 (406 mg/L), and the variability of specific conduc tance at an individual site decreases from upstream to down stream (fig. 47B). Variability in TDS is smallest (ranging from 276 to 708 mg/L) at the most downstream site RM1390), and largest (ranging from 211 to 736 mg/L) at the most upstream site (RM1481; Boughton and others, 2022, table 3-28).
82 Potential Effects of Energy Development, Williston Basin—Water Resources 100° 105° 110° 48° 45° !! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! !! !! ! !! ! ! ! !! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! !!! ! ! ! ! !! ! ! ! !! !! !! ! ! ! !! ! ! !! ! ! !!! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! !!! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! !! ! ! !! 100° 105° 110° !! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! !! !! ! !! ! ! ! !! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! !! !! !! ! ! ! !! ! ! !! ! ! !!! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! !! ! !! ! ! ! ! 48° 45° ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! !! ! !! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! !! !! ! ! ! !! ! ! !! ! ! !!! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! !! ! ! ! !! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! !! ! ! ! !! ! CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Maximum MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Median MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Minimum 30 to 2,500 2,501 to 5,000 5,001 to 10,000 10,001 to 25,000 25,001 to 50,000 50,001 to 75,000 75,001 to 116,000 Specific conductance, in microsiemens per centimeter at 25 degrees Celsius Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 EXPLANATION Williston Basin boundary Bakken Formation boundary ! ! ! ! ! ! ! MILES KILOMETERS Figure 43. Specific conductance in lakes in Montana, North Dakota, and South Dakota, from 1970 to 2014. A, minimum; B, median; and C, maximum.
Quality of Water Resources 83 Figure 44. Annual variability in values of constituents in all lakes across the Willison Basin by year from 1970 to 2014. A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter. A. Specific conductance for water years 1970-2014 B. Total dissolved-solids concentration for water years 1970-2014 1,000 10,000 100,000 1,000,000 1,000 10,000 100,000 Secondary maximum contaminant level Water year Specific conductance, in microsiemens per centimeter at 25 degrees Celsius Total dissolved-solids concentration, in milligrams per liter EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside
84 Potential Effects of Energy Development, Williston Basin—Water Resources Lower secondary maximum contaminant level Upper secondary maximum contaminant level Water year Secondary maximum contaminant level D. Sulfate concentration for water years 1970-2014 C. pH for water years 1970-2014 1,000 10,000 100,000 Sulfate, in milligrams per liter as sulfate pH, in standard units Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Figure 44. Annual variability in values of constituents in all lakes across the Willison Basin by year from 1970 to 2014. A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter.—Continued
Quality of Water Resources 85 1,000 10,000 100,000 Water year Chloride, in milligrams per liter as chloride Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Secondary maximum contaminant level E. Chloride concentration for water years 1970-2014 Figure 44. Annual variability in values of constituents in all lakes across the Willison Basin by year from 1970 to 2014. A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter.—Continued
86 Potential Effects of Energy Development, Williston Basin—Water Resources 31 30 31 16 6 48 64 52 86 59 24 16 48 50 31 30 31 16 6 48 64 52 84 59 58 50 39 50 D. Sulfate concentration for water years 1970-2014 Sulfate, in milligrams per liter as sulfate C. pH for water years 1970-2014 pH, in standard units A. Specific conductance for water years 1970-2014 Specific conductance, in microsiemens per centimeter at 25 degrees Celsius E. Chloride concentration for water years 1970-2014 Chloride, in milligrams per liter B. Total dissolved-solids concentration for water years 1970-2014 Total dissolved-solids concentration, in milligrams per liter Water year Water year Secondary maximum contaminant level Secondary maximum contaminant level Lower secondary maximum contaminant level Upper secondary maximum contaminant level Secondary maximum contaminant level at 250 milligrams per liter 31 30 30 16 6 47 64 52 86 59 59 49 1 31 30 31 16 6 48 64 52 83 59 54 53 40 50 31 30 31 17 5 48 64 52 86 59 55 53 41 50 EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside Figure 45. Annual variability in values of constituents in Lake Sakakawea by year from 1993 to 2014. A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter.
Quality of Water Resources 87 Values of pH varied spatially for sites across the Wil liston Basin (fig. 49), whereas pH variability was minimal for four select Lake Sakakawea sites (fig. 45C). Across the Williston Basin, pH was measured at 714 sites from 1970 to 2014 (Boughton and others, 2022, table 3-24). For most years, median pH values were within the EPA SMCL of 6.5 to 8.5 standard units (fig. 44C). At the four Lake Sakakawea sites, pH was consistently greater than 6.5 standard units, and 14 percent of the pH values exceeded the upper EPA SMCL of 8.5 standard units (fig. 47C). Of the 714 lake sites sampled across the basin, 528 sites had fewer than 10 samples (Boughton and others, 2022, table 3-24). An area of higher median pH was observed along the northern border of Mon tana and North Dakota (fig. 49). Similar to specific conduc tance and TDS, these samples were collected in 1983 as part of a special study (Boughton and others, 2022, table 3-24). Another area of high median pH was observed in Montana associated with a sample collected in 1990, which was the highest median concentration for the period (fig. 44C). Mea sured pH values in Lake Sakakawea varied minimally, both temporally and longitudinally (figs. 45C, 47C; Boughton and others, 2022, table 3-29). Median pH values in Lake Saka kawea ranged from 8.1 standard units in 2010 to 8.5 standard units in 2007 (fig. 45C; Boughton and others, 2022). Longi tudinally, median pH values in Lake Sakakawea were consis tently about 8.3 standard units (fig. 47C). Similar to specific conductance and TDS, sulfate con centrations measured at sites across the Williston Basin were spatially variable (fig. 50), while sulfate concentrations mea sured at select Lake Sakakawea sites were much less variable Water-surface elevation above National Geodetic Vertical Datum of 1929, in feet Water year Annual mean 1,830 1,850 1,840 1,820 1,810 1,800 EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] Figure 46. Annual mean water surface elevation in Lake Sakakawea from 1993 to 2014. (fig. 45D). Sulfate was measured at 474 sites in the Williston Basin from 1970 to 2014, and concentrations ranged from 0.1 to 54,000 mg/L (Boughton and others, 2022, table 3-25). In contrast, sulfate concentrations measured at four Lake Sakakawea sites from 1993 to 2014 ranged from 70 to 251 mg/L (Boughton and others, 2022, table 3-30). Of the 474 lake sites sampled across the basin, 351 sites had fewer than 10 samples, and 267 sites had median sulfate concentra tions that exceeded the EPA SMCL of 250 mg/L (EPA, 2009, 2012; Boughton and others, 2022, table 3-25). Consistent with specific conductance and total dissolved solids, high median sulfate concentrations were measured in samples along the northern border of Montana and North Dakota collected at several sites as part of a special project in 1983 (figs. 44D, 50). The highest single sulfate concentration measured in the Wil liston Basin was 54,000 mg/L, and this sample was collected from a site associated with this project. Also consistent with specific conductance and TDS, high sulfate concentrations measured at this group of sites resulted in a higher median value in the Williston Basin in 1983 (fig. 44D). Similar temporal and spatial patterns observed for specific conductance values and TDS concentrations were observed for sulfate concentrations within Lake Sakakawea. The highest median sulfate concentration of 225 mg/L was measured in 2013, and the lowest median sulfate concentra tion of 143 mg/L was measured in 2010 (fig. 45D). While an individual measurement at RM1481 (251 mg/L) exceeded 250 mg/L EPA SMCL, the median sulfate concentrations for Lake Sakakawea did not exceed the SMCL from 1993 through 2014. Spatially, median sulfate concentrations increase from upstream at RM1481 (142 mg/L) to downstream at RM1390 (163 mg/L), and the variability of sulfate concentrations at an individual site decreases from upstream to downstream (fig. 47D). Variability in sulfate concentrations is smallest (ranging from 121 to 230 mg/L) at the most downstream site (RM1390) and largest (ranging from 70 to 251 mg/L) at the most upstream site (RM1481; fig. 47D; Boughton and others, 2022, table 3-30). Chloride concentrations at sites across the Williston Basin were spatially variable (fig. 51), whereas chloride concentrations at select Lake Sakakawea sites were much less variable (fig. 45E). Chloride concentrations measured at 489 sites in the basin from 1970 through 2014 ranged from 0.4 to 10,500 mg/L (Boughton and others, 2022, table 3-26). In contrast, chloride concentrations at four Lake Sakakawea sites ranged from 3.5 to 13 mg/L from 1993 through 2014 (Boughton and others, 2022, table 3-31). Of the 489 lake sites sampled across the basin, 366 sites had fewer than 10 samples, and 36 sites had median chloride concentrations that exceeded the EPA SMCL of 250 mg/L (EPA, 2009, 2012). Samples collected for special projects in 1983 and 1990 identified an area of high median chloride concentrations along the northern border of Montana and North Dakota, potentially resulting in higher median concentrations in the basin for both years (figs. 44E, 51).
88 Potential Effects of Energy Development, Williston Basin—Water Resources D. Sulfate concentration for water years 1970-2014 A. Specific conductance for water years 1970-2014 E. Chloride concentration for water years 1970-2014 B. Total dissolved-solids concentration for water years 1970-2014 Sulfate, in milligrams per liter as sulfate Specific conductance, in microsiemens per centimeter at 25 degrees Celsius Chloride, in milligrams per liter Total dissolved-solids concentrations, in milligrams per liter RM1481 RM1445 RM1412 RM1390 Site number RM1481 RM1445 RM1412 RM1390 Site number Secondary maximum contaminant level Secondary maximum contaminant level at 250 milligrams per liter 207 Number of values Upper adjacent 75th percentile Median 25th percentile Lower adjacent Lower outside Lower detached Upper detached Upper outside EXPLANATION [Water year is defined as the 12-month period from October 1 through September 30 and is designated by the calendar year in which it ends] pH, in standard units C. pH for water years 1970-2014 Lower secondary maximum contaminant level Upper secondary maximum contaminant level Figure 47. Range and statistical distribution of A, specific conductance, in microsiemens per centimeter at 25 degrees Celsius; B, total dissolved solids, in milligrams per liter; C, pH, in standard units; D, sulfate, in milligrams per liter; and E, chloride, in milligrams per liter, measured at sites in Lake Sakakawea from 1993 to 2014. Sites listed in order from upstream to downstream.
Quality of Water Resources 89 100° 105° 110° 48° 45° !! !! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! !! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !!! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! !!! !! ! !! !! !!! ! ! ! !! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! !! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! !! ! 100° 105° 110° ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! !! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! !! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !!! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! !! ! ! ! !! ! ! ! ! !!! !! ! !! !! !!! ! ! ! !! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! !! ! ! ! ! !!! ! ! !!! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! !! ! 48° 45° ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! !! !! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !!! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! !!! !! ! !! ! !!! !!! ! ! ! !! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! !!! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! !! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! !!! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! !! !! ! ! ! ! ! ! CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Maximum MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Median MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Minimum 11 to 1,000 1,001 to 2,500 2,501 to 5,000 5,001 to 10,000 10,001 to 25,000 25,001 to 50,000 50,001 to 84,500 Total dissolved-solids concentration, in milligrams per liter EXPLANATION Williston Basin boundary Bakken Formation boundary Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 ! ! ! ! ! ! ! MILES KILOMETERS Figure 48. Total dissolved-solids concentrations in lakes in the Williston Basin in Montana, North Dakota, and South Dakota, 1970 to 2014. A, minimum; B, median; and C, maximum.
90 Potential Effects of Energy Development, Williston Basin—Water Resources 100° 105° 110° 48° 45° !! !! ! ! !! ! ! ! ! ! !!! ! ! !! ! ! ! ! !! !! !! ! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! !! ! !! !!! ! ! ! ! ! ! ! !! !! ! !! !! ! ! ! ! ! ! ! ! !! !! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! !! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !!! ! ! ! ! !! ! ! ! !! ! ! !!! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! !! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! !! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! ! !!! !! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! !! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! !! ! !! ! ! ! ! ! !! ! ! ! ! ! ! !!! ! ! !!! ! ! ! ! !! ! !! !! ! ! ! 100° 105° 110° ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! !! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! !! ! ! ! ! ! ! ! !! !! ! !!! ! ! ! ! ! !! !! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! !! !! ! ! !! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !!! ! ! ! !! ! ! ! !! !! !! ! ! ! ! ! !! ! ! !!! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! !! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! ! !!! !! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! !! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !!! ! ! !!! ! ! ! ! !! !! ! 48° 45° ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !!! ! ! ! ! ! !! !! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! !! !! !! ! ! ! !! ! !! ! ! !!! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! !! ! ! ! !! ! ! ! ! ! ! ! !! !! ! ! ! ! ! !! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! !!! ! ! ! ! ! !! ! !! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! !!! ! !! ! ! ! ! !! ! ! ! ! ! ! ! !! ! !! ! ! CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Maximum MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Median MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Minimum 0.7 to 5.0 5.1 to 6.0 6.1 to 7.0 7.1 to 8.0 8.1 to 9.0 9.1 to 10.0 ! ! ! ! ! ! ! 10.1 to 10.5 pH, in standard units EXPLANATION Williston Basin boundary Bakken Formation boundary Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 MILES KILOMETERS Figure 49. Values of pH in lakes in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 to 2014. A, minimum; B, median; and C, maximum.
Quality of Water Resources 91 Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 100° 105° 110° 48° 45° ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !!! ! !! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !!! !!! ! !! !!! ! ! ! ! ! ! !! ! !!! !! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! !! !! ! !! ! !! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !!! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! !! ! !! ! 100° 105° 110° ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !!! ! !! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! !! !!! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !!! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! !! ! ! !!! !! ! !! !! ! !! !! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! !! !! ! !!! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! !! ! !! !! ! !! ! 48° 45° ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! !! ! ! !!! ! ! ! ! !! ! !! !! !! !! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! !! ! !! ! !!! !!! ! !! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! !! !! !! !! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! !!! ! ! ! ! ! !! ! ! !! ! !! !! ! ! ! ! CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Maximum MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Median MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Minimum 0.1 to 250 251 to 500 501 to 1,000 1,001 to 5,000 5,001 to 10,000 10,001 to 25,000 25,001 to 54,000 Sulfate concentration, in milligrams per liter EXPLANATION Williston Basin boundary Bakken Formation boundary ! ! ! ! ! ! ! MILES KILOMETERS Figure 50. Sulfate concentrations in lakes in the Williston Basin in Montana, North Dakota, and South Dakota, from 1970 through 2014. A, minimum; B, median; and C, maximum.
92 Potential Effects of Energy Development, Williston Basin—Water Resources 100° 105° 110° 48° 45° !! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !!! ! ! !! !! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! !! !! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! !! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! !! !! ! ! ! ! ! ! ! ! ! !! !! ! 100° 105° 110° ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !!! ! ! !! !! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! !! !! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! !! ! ! !! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! !! !! ! 48° 45° ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! !!! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! !! !! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !!! ! ! !! !! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! !! ! ! !! ! ! ! !! ! ! ! ! !! !! ! !! ! !! !! !! !! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! !! !! ! CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Maximum MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Median MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Minimum 0.4 to 100 101 to 250 251 to 500 501 to 1,000 1,001 to 2,500 2,501 to 5,000 5,001 to 10,500 Chloride concentration, in milligrams per liter Williston Basin boundary Bakken Formation boundary Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 EXPLANATION ! ! ! ! ! ! ! MILES KILOMETERS Figure 51. Chloride concentrations in lakes for Montana, North Dakota, and South Dakota, from 1970 through 2014. A, minimum; B, median; and C, maximum.
Produced Water 93 Within Lake Sakakawea, there is minimal temporal and spatial variability in measured chloride concentrations (figs. 45E, 47E); the highest median chloride concentra tion of 10.5 mg/L was measured in 2013, and the lowest median chloride concentration of 8.25 mg/L was measured in 1997 (fig. 45E). Median chloride concentrations for Lake Sakakawea did not exceed the 250 mg/L EPA SMCL from 1993 through 2014. Spatially, median chloride concentra tions increase slightly from upstream (8.1 mg/L) at RM 1481 to downstream (9.6 mg/L) at RM 1390, and the variability of chloride at an individual site decreases from upstream to downstream (fig. 47E). Variability in measured chloride con centrations is smallest (ranging from 5 to 11 mg/L) at the most downstream site at RM 1390 and largest (ranging from 3.5 to 13 mg/L) at the most upstream site at RM 1481 (fig. 47E). Data for 1 or more of the 10 trace metals were available at 377 lake sites in the Williston Basin from 1993 through 2014 (table 10; Boughton and others, 2022, table 3-32). Chromium, copper, and lead rarely were detected in samples (table 10). The maximum detected concentrations for barium, chromium, copper, lead, selenium, and zinc for each site did not exceed EPA MCLs SMCLs, or ALs (EPA, 2009, 2012). For aluminum, arsenic, and iron, the maximum detected concentrations (6,820, 516, and 7,220 µg/L, respectively) exceeded comparable EPA MCLs or SMCLs of 50 or 200, 10, and 300 µg/L, respectively (table 10). Few trace metal data were available for Lake Sakakawea and are not presented here. Produced Water During conventional and unconventional oil and gas development, large volumes of coproduced fluids (hereinafter termed "produced water") are brought to the surface along with the targeted hydrocarbons as part of the oil and gas exploration and extraction processes (fig. 52). Produced water may include formation water (waters that coexist with rock/oil); hydraulic fracturing fluids (predominantly "fresh" waters with chemi cal additives and proppants used in the hydraulic fracturing process); and other combinations of water and chemicals used during drilling, development, treatments, recompletions, and workovers. Produced water represents waters generated from an oil or gas well, including the fluid retrieved during and after the completion of hydraulic fracturing (flowback waters), water produced immediately after hydraulic fracturing with composi tions close to those of the injected fluid, and waters produced after months or years of production, whose compositions resemble formation water (Rowan and others, 2011). Produced water is generated throughout the lifetime of an oil-producing well. The Williston Basin yielded more than 1 million bbl of oil per day in early 2014 and averaged more than 600,000 bbl per day of wastewater produced from wells completed in the Bak ken, Three Forks, and Tyler Formations in March 2014 alone (Gordon and Garner, 2014). Produced water to oil ratios, aver aged by square-mile section for Bakken and Three Forks wells Oil Produced water Figure 52. Oil and produced water collected from an unconventional Bakken Formation production well near Sidney, Montana, August 2014. Photograph by Gregory Delzer, U.S. Geological Survey. drilled from 2007 to 2014, ranged from ratios of 0.1:1 to greater than 70:1 for wells during their initial oil production; reportedly, the ratio of produced water to oil typically increases during the life of a well (Gordon and Garner, 2014). The bulk fluid discharged at the oil-production well is sep arated into oil and water components at local separator facilities. The produced water is typically stored onsite for a period and then hauled by truck or piped to a treatment or disposal facility. Historically, brines were discharged directly into surface water or earthen evaporation pits (McMillion, 1965; Gorman, 1999). North Dakota established rules prohibiting use of reserve pits for storage of fluids generated during well completion (North Dakota Legislative Branch, 2013a); therefore, large volumes of these brines are now injected into deep geologic formations using disposal wells (Gleason and others, 2011). Development of a Produced Water-Quality Dataset The water chemistry of produced water of the Williston Basin was evaluated and summarized using two datasets: (1) selected data retrieved from the USGS National Produced Waters Geochemical Database (NPWGD) v2.1 on May 25, 2015 (Blondes and others, 2014), and (2) data specifically collected through USGS efforts to evaluate the chemical and isotopic characteristics of produced waters from the Bakken and Three Forks Formations from 2010 to 2014 (Peterman and others, 2017; Boughton and others, 2022, tables 4-1, 4-2). The water-quality data from the NPWGD and USGS samplecollection efforts are summarized and described in relation to general water-chemistry, source formations, and constituents of concern. These data have been made available in a data release (Boughton and others, 2022, tables 4-1, 4-2).
94 Potential Effects of Energy Development, Williston Basin—Water Resources U.S. Geological Survey National Produced Waters Geochemical Database The USGS NPWGD includes nearly 162,000 produced water and other deep-formation water samples of the United States (Blondes and others, 2014). The NPWGD data contain a considerable range of reported values for most of the chemi cal constituents (Blondes and others, 2014). As discussed in Blondes and others (2014), data included within the NPWGD originate from a variety of sources that cannot be verified and are considered provisional. Despite these limitations, the NPWGD may be a source to obtain a general understanding of the geochemistry of produced waters, specifically major ion data associated with oil development processes in the United States. Data retrieved from the NPWGD were restricted to include only sample sites that included the following: (1) reported locations (latitudes and longitudes) within the boundaries of the Williston Basin and the extent of the Bakken Formation within Montana, North Dakota, and South Dakota; and (2) geologic formation designations. The resulting dataset includes 10,659 samples from 3,361 sites identified with unique American Petroleum Institute numbers. Also included in table 4-1 of Boughton and others (2022) are 106 samples lacking American Petroleum Institute numbers, but that have data for the most commonly reported water-quality constitu ents or properties (pH, specific conductance, calcium, chloride, magnesium, potassium, sodium, bicarbonate, and sulfate). Although many of these samples have associated well names, it is unclear if they represent unique sites or possibly duplicate sites. The NPWGD also includes the geochemical results of samples collected from a variety of collection points or condi tions, including drill-stem tests, well heads, separators, heater treaters, discharge lines, water line, well head samples, water dump, production, swab test, and many others. Data included in Boughton and others (2022, table 4-1) are shown as retrieved from the NPWGD with the exceptions of the deletions of several columns and the addition of the two columns: generalized geologic unit and comments. The NPWGD data retrieval included "formation" designations ("Formation" column) of the geologic formation associated with the sample. Instead of using the 387 unique "forma tion" designations included in the original database retrieval, a "generalized geologic unit" designation was developed that primarily was based on the interpretation of formation and age information provided in the database in combination with analysis of the USGS National Geologic Map Database (USGS and the American Association of State Geologists, 2012) and the North Dakota stratigraphic column (Bluemle and others, 1986). The generalized geologic units of several samples were designated as "undifferentiated" within a geo logic age if a specific age could not be confidently determined with the available data. The comment column was added at the end of the table and includes remarks related to the analyses. Data descriptions and summary statistics of the NPWGD were completed using filtered data based on geochemical quality-control criteria stated in Blondes and others (2014). These criteria included culling the data if any of the follow ing conditions were met: (1) magnesium concentration greater than calcium concentration, (2) potassium concentration greater than chloride concentration, (3) potassium concentra tion greater than five times the sodium concentration, and (4) ion charge balances greater than 5 percent. Resulting samples used for descriptive analysis and summary statistics included 10,178 of the 10,659 samples with formation infor mation retrieved from the NGPWD (Boughton and others, 2022, table 4-1). U.S. Geological Survey Produced Water Data, 2010 through 2014 The USGS collected samples from 2010 through 2014 to evaluate the chemical and isotopic characteristics of produced waters (Peterman and others, 2017; Boughton and others, 2022, table 4-2) from wells located within the Bakken Forma tion boundary (fig. 53) that were screened in either the Bakken or Three Forks Formation (figs. 2, 3). These samples were either specifically collected by USGS personnel or by opera tors that sent the samples directly to the USGS. The data rep resent site-specific samples collected directly from wellheads or separators at oil-production wells that had typically been in production for at least 6 months. The produced water fraction of samples collected at the wellheads were processed (filtered and acidified) after the oil and water separated. Samples col lected directly from separators were processed without the need for oil and water separation. Samples were analyzed for field properties, inorganics (major ions and trace elements), stable isotopes of hydrogen and oxygen, radium isotopes, and strontium isotopes at USGS laboratories or contract labora tories (table 11). Quality-assurance samples, including field replicates and lab replicates, accounted for 10 to 15 percent of the samples collected. These samples analyzed by USGS have linked ancillary information including well logs and analytical procedures, oftentimes production history, and treatment con ditions. In general, this ancillary information is not available for sample analyses retrieved from the NPWGD. Initial reconnaissance samples were collected on June 6, 2010, from separators at two well sites that had been in production for at least 6 months. Produced-water samples were collected on October 15 and 16, 2012, directly from the well heads of six oil-production wells and from separators at three sites. In an attempt to limit the presence of hydraulic fracturing fluid and examine the "end-member" composition of the produced water, sites were selected that had been in production for at least 1 year. A secondary sampling effort on August 12, 2014, was designed to specifically examine safety concerns and produced water sample collection methodol ogy. On August 12, 2014, samples were collected from the wellheads and separators at five oil-production wells (Rodney Caldwell, USGS, written commun., 2015). Efforts were made to ensure that more than 1 year had passed since these wells
Produced Water 95 had been hydraulically fractured, and that they had not been flushed or treated for at least 7 days before sampling. In addi tion, a series of samples from each site were processed (fil tered and acidified) at set periods (about 1 hour, 4 hours, and 24 hours) after the original oil and water composite sample was collected from the wellhead to examine how holding times affect the chemistry of these waters. In 2014, additional samples were collected from the separators by operators and shipped directly to the USGS (Zell Peterman, USGS, written commun., 2015). General Quality of Produced Water The TDS in water, commonly termed salinity, is typically expressed in milligrams per liter, and water can be classified by TDS as follows: (1) fresh, 0 to 1,000 mg/L; (2) slightly saline, 1,000 to 3,000 mg/L; (3) moderately saline, 3,000 to 10,000 mg/L; (4) very saline, 10,000 to 35,000 mg/L; and (5) briny, greater than 35,000 mg/L (Heath, 1983). Often, only freshwater is suitable for drinking water, irrigation, and industrial uses. Produced waters are often brines that are more saline than seawater (table 12). Produced waters also can contain dispersed oil, dissolved organic compounds, radionuclides, bacteria, and solids (Veil and others, 2004). In produced waters of the United States, sodium is the most commonly detected cation, and chloride or bicarbonate are the most commonly detected anions (Guerra and others, 2011). Produced waters of the Williston Basin are exceedingly high in dissolved solids concentrations, with some of the highest TDS concentrations measured in the oil and gas production areas of the central and western United States (fig. 54). The generalized water chemistry of samples collected from (1) the top three oil-producing geologic units (Bakken Formation, Madison Group, and Red River Formation) in the Williston Basin (NPWGD); (2) groundwater water-supply wells from the upper Fort Union Formation (McMahon and others, 2014); and (3) mean seawater (Hem, 1989) are presented in table 12. The median TDS concentration of the produced water from units in the Williston Basin is about 278,000 mg/L, about eight times more saline than modern seawater (table 12). In comparison, TDS concentrations of produced water in the Appalachian Basin, which includes the Marcellus Shale, typically range from 100,000 to 300,000 mg/L (Rowan and others, 2015). Median TDS concentration of the producedwater samples (all units; 277,725 mg/L) was about 200 times greater than the median TDS concentration (1,369 mg/L) of EXPLANATION Produced-water sample and American Petroleum Institute number Williston Basin boundary Bakken Formation boundary Base map modified from U.S. Geological Survey and Esri digital data, variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 105° 100° 110° 48° 45° ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 250832289 3305305290 3305303527 2508322918 3305304180 3305303977 2508322956 3306100880 3305304162 3306102309 3306102308 3302501567 3305500135 3302500971 3302501247 3310501685 2508322884 3305303971 3310501688 3305304707 3305305031 2508322963 2508322963 3305303915 3305303702 3301301653 3306101312 3301301584 3305303292 2508323159 2508323132 MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA 30 MILES 30 KILOMETERS MONTANA NORTH DAKOTA LAKE SAKAKAWEA Figure 53. Location of 30 oil-production well sites within the Williston Basin for which the U.S. Geological Survey analyzed samples, 2010 through 2014.
96 Potential Effects of Energy Development, Williston Basin—Water Resources Table 11. Constituent list for characterization of produced waters in the Williston Basin, 2010 through 2014. [NA, not applicable; CGCSRL, Geophysics and Geochemistry Science Cen ter Laboratory, Lakewood, Colorado; RSIL, U.S. Geological Survey Reston Stable Isotope Laboratory, Reston, Virginia; NWQL, National Water Quality Laboratory] Analyte group Analyte class Laboratory pH, temperature, specific conductance, specific gravity, and alkalinity Field parameters NA Inorganics—major ions and trace elements Inorganics CGCSRL Hydrogen and oxygen isotopes of water Isotopes RSIL Radium-226 and radium-228 Radiochemical NWQL contract laboratory. Strontium-87/strontium-86 Isotopes CGCSRL groundwater samples collected from the upper Fort Union Formation (table 12). The major-ion chemistry of producedwater samples are typically dominated by sodium and chlo ride, whereas domestic and water-supply samples from the upper Fort Union Formation are typically calcium-magnesium bicarbonate type waters (McMahon and others, 2014). The distribution of USGS NPWGD discrete water-quality samples associated with the Bakken Formation are focused near the center of the Williston Basin, mostly in North Dakota, whereas the greater number of samples identified from wells producing from the Red River Formation, Madison Group, and other or undifferentiated geologic units include sites distributed across the Williston Basin (fig. 55). TDS concen trations of samples collected near the margins of the Williston Basin are typically among the lowest (less than 50,000 mg/L), whereas samples with the highest TDS concentrations (greater than 250,000 mg/L) are typically near the central Williston Basin. Only about 2 percent of the samples from the small number of wells (384) associated with the Bakken Forma tion have TDS concentrations less than 50,000 mg/L (figs. 55, 56). Samples collected from the Madison Group, Red River Formation, and other or undifferentiated geologic units show a greater variability of TDS concentrations within the central Williston Basin (fig. 56). General physical properties and major-ion chemistry of produced-water samples collected from wellheads and separators by the USGS or supplied to the USGS from opera tors within the Williston Basin of Montana and North Dakota were less variable than data from the NPWGD (Boughton and others, 2022, tables 4-1, 4-2). In addition, most major ion and TDS concentrations, measured in samples from Bak ken Formation oil-production wells from the USGS studies were higher than the results from the NPWGD (table 13). In general, USGS samples from 2010-2014 were consistently collected, processed, and analyzed, and the sites selected were actively producing wells that were not sampled during periods of drilling and hydraulic fracturing. In addition, an attempt was made to avoid wells that were actively being treated through the addition of scale inhibitors or "freshwater" flushing. Table 12. Generalized water chemistry of produced waters collected within the Williston Basin, including samples collected from the Bakken Formation, the Madison Group, and Red River Formation; groundwater samples collected from water-supply wells in the upper Fort Union Formation in Montana and North Dakota; and typical seawater. Constituent Median concentration, in milligrams per liter (number of results) Average concentration, in seawater3, in milligrams per liter All units1 Bakken Formation1 Madison Group1 Red River Formation1 Upper Fort Union Formation2 Calcium 9,282 (10,178) 12,698 (404) 9,209 (5,490) 6,443 (1,273) 199 (30) Magnesium 1,004 (9,993) 1,004 (404) 1,076 (5,399) 741 (1,213) 97 (30) 1,350 Sodium 82,500 (10,178) 77,953 (404) 93,100 (5,490) 55,061 (1,273) 39 (30) 10,500 Potassium 2,780 (4,473) 4,100 (355) 2,610 (2,257) 2,755 (522) 5 (30) Bicarbonate 236 (9,890) 183 (396) 240 (5,486) 256 (1,205) 534 (30) Sulfate 860 (10,117) 488 (401) 966 (5,659) 945 (1,257) 464 (30) 2,700 Chloride 168,000 (10,178) 153,157 (404) 173,501 (5,490) 125,276 (1,273) 9 (30) 19,000 Total dissolved solids 277,725 (9,968) 251,150 (384) 286,437 (5,376) 219,281 (1,258) 1,369 (30) 34,579 1Blondes and others (2014). 2McMahon and others (2014). 3Hem (1989).
Produced Water 97 Total dissolved-solids concentration, in milligrams per liter 1,000,000 10,000 1,000 100,000 Williston—total Williston—Montana Wind River Los Angeles Permian Anadarko San Juan Central Kansas San Joaquin Paradox—Utah Paradox—Colorado Paradox—total Unita-Piceance Denver Green River Big Horn Powder River Williston—South Dakota Williston—North Dakota EXPLANATION Upper adjacent 75th percentile Median 25th percentile Lower adjacent Oil and gas production area Figure 54. The distribution of total dissolved solids in produced waters from geologic formations in the United States (Benko and Drewes, 2008). Water-Quality Constituents of Concern in Produced Water Produced waters can be a resource for several beneficial uses, and constituents in produced waters have been used for their economic value (Guerra and others, 2011; Engle and others, 2014); however, produced waters within the Willis ton Basin are not considered a viable resource for most uses (drinking water, livestock, irrigation, and so on) because of extreme salinity and other constituent issues. Inadvertent environmental releases of produced waters with extreme salinities and potentially elevated concentrations of constitu ents could negatively affect groundwater and surface-water resources. Available NPWGD data indicate that produced waters often far exceed EPA MCLs and SMCLs. Major-ion and some trace-element concentrations are commonly elevated in produced waters (table 14). Median values for TDS and chloride concentrations were 555 and 672 times the respective SMCLs. Sulfate concentrations exceeded the SMCL in about 86 percent of samples. Chromium concentrations exceeded the MCL in more than 96 percent of samples, whereas all arsenic concentrations (ranging from 243 to 506 μg/L) exceeded the MCL (table 14). Concentrations of cadmium, fluoride, lead, selenium, and zinc also exceeded drinking-water standards (MCL or AL) in 36 percent or more of the samples. Water-quality data collected by the USGS within the Wil liston Basin from 2010 through 2014 include constituents that are not commonly available in the NPWGD (table 15). Majorion chemistry was similar to that of the NPWGD, although all the USGS samples exceeded SMCL values for TDS and chloride concentrations (table 15). Arsenic concentrations exceeded the MCL, and manganese exceeded the SMCL in samples from all sites analyzed. Barium, cadmium, lead, sulfate, and zinc concentrations exceeded MCLs or SMCLs in samples from 50 percent or more of the sites analyzed. Com bined radium-226 and radium-228 activity levels exceeded the MCL for all the USGS samples. The combined radium-226 and radium-228 activity levels in USGS samples ranged from 541 to 6,020 picocuries per liter (pCi/L), with a median of 3,695 pCi/L, which is about 739 times greater than the MCL (table 15). The total ammonia nitrogen (ammonia plus ammonium) aquatic life water quality criteria is 17 mg/L for acute toxicity and 1.9 mg/L for chronic toxicity at pH 7 and 20 degrees Celsius (EPA, 2013a). Ammonium concentrations in samples from two wells ranged from 1,610 to 2,240 mg/L (Boughton and others, 2022, table 4-2). Characterization of Produced Water General chemical characteristics of produced-water samples obtained from the geologic units in the Williston Basin indicate that nearly all these waters are extremely saline sodium-chloride brines. With ever-changing extraction and disposal practices in the Williston Basin, it is important to
98 Potential Effects of Energy Development, Williston Basin—Water Resources 100° 105° 110° 48° 45° 100° 105° 110° 48° 45° CANADA MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA C. Madison MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA CANADA UNITED STATES B. Bakken MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES CANADA D. Undifferentiated MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA UNITED STATES UNITED STATES A. Red River !! ! ! ! ! ! ! ! !! ! !! !! !! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !!! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! !! ! ! ! ! !! !!! !! ! !! ! ! ! !! ! !! ! ! ! !! ! ! ! ! ! !!! !! !!! ! !! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! !!! !! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! !!! ! ! !! ! ! !! ! !! !! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! !! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! !! ! ! ! ! ! ! !!! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! !! !!! ! ! ! ! ! !!! ! ! !! !! !! ! !! ! !! !! ! ! ! !! !!! ! !!! ! ! !! !! !!! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !!! !! !! ! ! ! ! ! !!! !!! ! ! ! ! !!! ! !! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !!! !!! !! ! ! !! !! ! ! ! ! !! ! ! ! ! ! ! ! ! !!! !! !!! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! !!! ! ! ! ! ! ! ! ! ! !! !! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! !!! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! !! ! ! ! !! !! !!! ! ! ! ! ! ! ! !! !! ! ! ! !!! ! !! ! !! !!! ! ! !!! !! ! ! ! ! ! !! ! ! ! ! ! !! !! !! ! !! ! !! !! ! ! !! ! ! ! !! ! !! !! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !!! ! ! ! !! !! !! ! ! !! !! ! ! ! ! ! !! ! !! !! ! !! ! !! ! ! !! ! ! ! ! ! ! !! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! !! ! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! !! ! !!! ! ! !! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! !! !! ! !!! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! !! ! ! !! !!! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! !! ! !! !! ! ! ! ! ! ! ! ! ! ! !! ! !!! !! ! ! !! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! !! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! !!! !! ! ! ! !! ! ! !! ! ! ! ! ! ! !! ! ! ! !! ! !! !! ! ! !! ! !! ! !! ! ! !! !! !! ! ! !! ! ! !! !!! !! ! ! !! ! ! ! ! ! ! !!! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! !!! !! ! ! !! !! ! !! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! !! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! !! ! !! ! !! !! ! !! ! !! ! ! ! ! ! ! !! !!! ! !! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !!! ! ! ! ! !!! !! ! !!! ! !! !! ! ! !! ! ! ! !! ! ! !! !! ! ! ! ! !! ! ! ! ! !! ! ! !!! !! !! !! ! ! !!! !! ! ! !! !! !!! ! ! ! !!! !! !! ! ! ! ! !! !! ! !! ! ! ! ! !! !! !! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! !!! !! ! !! !! ! ! ! ! !! ! ! ! !! ! !! ! ! ! !! !!! !! !!! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !!! ! !! ! ! ! ! ! !!! ! ! ! !! ! !! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! !! ! ! ! !! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! !! !! ! ! !! ! ! ! ! !! ! !!! ! ! ! ! !! ! ! !! !! ! !! ! ! ! ! !! ! ! !! ! !! ! !! ! !!! !! !!! !! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! !! ! !!! ! ! ! ! ! !! ! ! !!! ! ! ! !! ! ! ! !! ! ! !! ! ! !! ! ! ! ! ! ! ! !! ! ! !! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! !! !!! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !!! !! !! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !!! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! !! ! !! ! ! ! ! ! ! !!! !! ! ! ! ! !! !! ! ! ! ! !!! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! !! ! ! ! ! ! !! !!! ! !! !! ! ! !! ! ! ! !! !!! ! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! !! ! ! !! !! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! !! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! !! ! !! ! ! ! ! !! !! ! !! ! ! ! !!! !! ! ! ! ! ! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! !! ! ! ! ! ! !! ! !! !! ! ! ! ! ! ! ! ! !!! ! ! ! !! ! !! !! ! ! ! ! !! ! ! !! !! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! ! ! ! !!! !! !! !!! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! !! !! !!! !! !! !! !! ! !!! !!! ! ! !! ! ! ! !!! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! ! !! ! ! ! ! !!! !! !!! ! !! ! ! ! ! !! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !!! ! !! ! !! ! ! ! !! ! ! ! ! ! ! ! !! ! !! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! !! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! !! !! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! !! ! ! ! ! ! !! ! ! !! ! !! ! ! ! ! ! !! ! !!! !!! ! ! ! !!! ! ! ! !! !!! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! !! ! ! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! !! ! !!! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! Total dissolved-solids concentration, in milligrams per liter ! Less than 50,000 ! 50,000 to 250,000 ! Greater than 250,000 EXPLANATION Williston Basin boundary Bakken Formation boundary Base map modified from U.S. Geological Survey, Esri, Commission for Environmental Cooperation, and Western States Data Aggregation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 MILES KILOMETERS Figure 55. Spatial distribution of total dissolved-solids concentrations, in milligrams per liter, for samples included in the U.S. Geological Survey National Produced Waters Geochemical Database in Montana, North Dakota, and South Dakota. A, Red River Formation; B, Bakken Formation; C, the Madison Group; and D, other or undifferentiated geologic units.
Produced Water 99 All (undifferentiated) Madison Group Bakken Formation Red River Formation All (undifferentiated) Madison Group Bakken Formation Red River Formation Chloride, in milligrams per liter Total dissolved-solids concentration, in milligrams per liter Calcium, in milligrams per liter Sodium, in milligrams per liter 10,178 5,490 1,273 9,968 5,376 1,258 10,178 5,490 1,273 10,178 5,490 1,273 200,000 150,000 100,000 50,000 200,000 150,000 100,000 50,000 250,000 350,000 300,000 200,000 100,000 300,000 600,000 400,000 500,000 140,000 20,000 40,000 100,000 60,000 80,000 160,000 120,000 10,178 Number of values EXPLANATION Largest value within 1.5 times interquartile range above 75th percentile 75th percentile Median 25th percentile Smallest value within 1.5 times the interquartile range below 25th percentile Outside value—Value is >1.5 and times the interquartile range beyond either end of the box Outside value—Value is >1.5 and times the interquartile range beyond either end of the box Geologic unit Geologic unit Interquartile range Figure 56. Range and statistical distribution of concentrations of calcium, sodium, chloride, and total dissolved solids in producedwater samples from the Williston Basin, Montana, North Dakota, and South Dakota, including all samples in the U.S. Geological Survey National Produced Waters Geochemical Database (All) as well as from the Madison Group, Bakken Formation, and Red River Formation.
100 Potential Effects of Energy Development, Williston Basin—Water Resources Table 13. Generalized water chemistry of produced-water samples collected from the Bakken and Three Forks Formations, Williston Basin, Montana and North Dakota as part of U.S. Geological Survey study efforts 2010 through 2014 and Bakken Formation samples included in the U.S. Geological Survey Produced Waters Geochemical Database v2.1. [USGS, U.S. Geological Survey] Constituent Median concentration, in milligrams per liter (number of wells) Bakken Formation1 Bakken Formation USGS samples 2010-142 Three Forks Formation USGS samples 2010-142 Calcium 12,698 (404) 18,950 (25) 20,600 (3) Magnesium 1,004 (404) 1,400 (25) 1,400 (3) Sodium 77,953 (404) 83,100 (25) 84,700 (3) Potassium 4,100 (355) 6,740 (25) 6,410 Bicarbonate 183 (396) 205 (12) 210 (1) Sulfate 488 (401) 386 (25) 435 (3) Chloride 153,157 (404) 187,000 (25) 198,000 (3) Total dissolved solids 251,150 (384) 299,000 (25) 322,000 (3) 1Blondes and others (2014). 2USGS data collection efforts during 2010-14. Based on median values of samples from individual wells (Peterman and others, 2017; Boughton and others, 2022, table 4-2). Table 14. Summary of concentrations of selected chemical constituents in produced-water samples stored in the U.S. Geological Survey Produced Waters Geochemical Database v2.1 for sites within the Williston Basin, Montana, North Dakota, and South Dakota. [µg/L, microgram per liter; MCL, maximum contaminant level; NQ, not quantified; mg/L, milligram per liter; SMCL, secondary maximum contaminant level] Constituent (units) Number of samples Concentration range1 Median concentration1 U.S. Environmental Protection Agency drinking-water regulation2 Number of samples that exceeded the regulation Arsenic (µg/L) 243 to 506 10 (MCL) Barium (µg/L) NQ to 1,400 2,000 (MCL) Cadmium (µg/L) NQ to 67 NQ 5 (MCL) Chloride (mg/L) 10,178 20 to 331,400 168,000 250 (SMCL) 10,119 Chromium (µg/L) 1,792 NQ to 2,204 100 (MCL) 1,730 Fluoride (mg/L) 0.81 to 17.0 4 (MCL) Iron (µg/L) 4,806 NQ to 10,000 300 (SMCL) Lead (µg/L) NQ to 1,210 NQ 15 (action level) Manganese (mg/L) NQ to 17.0 50 (SMCL) Selenium (µg/L) 0.04 to 1,560 50 (MCL) Sulfate (mg/L) 10,117 NQ to 17,751 250 (SMCL) 8,693 Zinc (µg/L) NQ to18,100 NQ 5,000 (SMCL) Total dissolved solids (mg/L) 9,968 NQ to 546,300 277,725 500 (SMCL) 9,950 1Concentrations were reported as none detected, absent, negative, trace, minor, present, or a qualitative description of some amount and are generalized as NQ. NQ values were ranked the lowest for median calculations. 2U.S. Environmental Protection Agency (EPA, 2009, 2012). A MCL is the maximum permissible level of a contaminant in water delivered to users of a publicwater system and is a health-based enforceable regulation. SMCLs are nonenforceable guidelines regarding cosmetic or aesthetic effects of drinking water. An action level (AL) is the concentration of copper or lead in drinking water at or above which additional steps are required to reduce the constituent concentration (EPA, 2009, 2012). For regulatory purposes, the AL is applied only to tap water samples, and only if more than 10 percent of the samples exceeded the AL.
Produced Water 101 Table 15. Summary of selected physical properties and chemical constituents collected within the Williston Basin area of Montana and North Dakota, and analyzed by U.S. Geological Survey, 2010 through 2014. [µg/L, microgram per liter; MCL, maximum contaminant level; mg/L, milligram per liter; NQ, not quantified; SMCL, secondary maximum contaminant level; pCi/L, picocurie per liter; less than] Constituent (units) Number of wells Concentration range1 Median concentration1 U.S. Environmental Protection Agency drinking-water regulation2 Number of wells that exceeded the regulation Arsenic (µg/L) 63 to 566 10 (MCL) Barium (µg/L) 1,410 to 50,900 24,650 2,000 (MCL) Cadmium (µg/L) NQ to 95 5 (MCL) Chloride (µg/L) 32,000 to 210,000 187,500 250 (SMCL) Lead NQ to 1,210 15 (action level) Manganese (µg/L) 1,540 to 35,400 14,850 50 (SMCL) Radium-226 and radium-228 (pCi/L) 541 to 6,020 3,695 5 (MCL) Sulfate (mg/L) 158 to 579 250 (SMCL) Uranium (µg/L) NQ to 3 NQ 30 (MCL) Zinc (µg/L) NQ to 31,000 13,450 5,000 (SMCL) Total dissolved solids (mg/L) 51,617 to 346,176 302,073 500 (SMCL) 1Values were reported as none detected, absent, negative, trace, minor, present, or a qualitative description of some amount and are generalized as NQ. NQ values were ranked the lowest for median calculations. Based on median values of samples from individual wells (Peterman and others, 2017; Boughton and others, 2022, table 4-2). 2U.S. Environmental Protection Agency (EPA, 2009, 2012). An MCL is the maximum permissible level of a contaminant in water delivered to users of a pub lic-water system and is a health-based enforceable regulation. SMCLs are nonenforceable guidelines regarding cosmetic or aesthetic effects of drinking water. An action level (AL) is the concentration of copper or lead in drinking water at or above which additional steps are required to reduce the constituent concentra tion (EPA, 2009, 2012). For regulatory purposes, the AL is applied only to tap water samples, and only if more than 10 percent of the samples exceeded the AL. 3Twenty wells had reported lead concentrations greater than the AL of 15 µg/L. Seven additional wells had NQ results (less than values) at levels higher than the AL of 15 µg/L with reported values of <19 to <180 µg/L. characterize produced waters from the different source forma tions. Below are descriptions of studies to characterize water sources using standard water chemistry as well additional geochemical tools, such as isotope analysis. The difference in TDS between potable and produced waters has been used to identify groundwater resources affected by brine within the Williston Basin. As produced waters typically have high TDS concentrations, the measure ment of apparent conductivity and resistivity (the inverse of electrical conductivity) differences between potable and produced waters has been used to identify groundwater resources affected by produced waters. Borehole, groundbased, and airborne geophysical surveys have been done in the Williston Basin to map subsurface variations in resistivity (the inverse of electrical conductivity) and electromagnetic readings (expressed as apparent conductivity), particularly in areas that have been developed for energy resources (Murphy and Kehew, 1984; Reiten and Teschmak, 1993; Thamke and Craigg, 1997; Thamke and Smith, 2014). Early geophysi cal resistivity surveys in northwestern North Dakota were completed by Murphy and Kehew (1984) to map areas of high salinity (low resistivity and high conductivity) around oil and gas well sites. Reiten and Teschmak (1993) completed electro magnetic conductivity surveys (reported as apparent conduc tivity) in Sheridan County, Mont., to map saline waters near oil and gas well sites. In early 2000s, the USFWS assessed groundwater salinity in several wildlife protection areas that were spatially associated with energy development (Rouse and others, 2013). Maps made from these data to assess possible plumes of high salinity showed that all the sites investigated had areas of anomalously high electrical conductivity. Groundbased geophysical measurements were made by Preston and others (2012, 2014a, b) in several areas near USFWS sites, including areas that had been previously surveyed by Reiten and Teschmak (1993). The survey results were used in asso ciation with auxiliary information, such as water chemistry samples or geologic maps, to interpret the source of variations in the geophysical profiles and map areas of variable salinity. Naturally saline and brine-contaminated soil and groundwa ter can both result in elevated apparent conductivity, so the availability of groundwater chemistry data was important to differentiate between the two types of salinity. In areas that had been previously surveyed, locations of high electrical conductivity values had migrated with time.
102 Potential Effects of Energy Development, Williston Basin—Water Resources The East Poplar oil field on the Fort Peck Indian Reserva tion in the western Williston Basin is an example of an inte grated hydrologic, geologic, and geophysical study of a brinecontaminated area that began in the early 1990s (Thamke and Craigg, 1997). Borehole, ground, and airborne electromagnetic apparent conductivity data were collected in the 106 mi2 area and used to determine extent of brine contamination (Smith and others, 2006a, b, 2014). These data were collected and interpreted in conjunction with water-quality data collected through 2009 to delineate brine plumes in the shallow aquifers (Thamke and Smith, 2014). Monitoring wells subsequently were drilled in some areas without existing water wells to confirm most of the delineated brine plumes; however, several possible plumes do not contain either existing water wells or monitoring wells. Clayton and others (1966) analyzed oxygen and hydrogen isotopes of produced water from several basins to show that brines were largely of meteoric origin (precipitation such as rain or snow). Later studies have determined that these waters are complex mixtures of meteoric and marine sources (Hoefs, 2009). As described by Connolly and others (1990), forma tion waters may originate as meteoric water recharged through and reacting with the rock column or as connate water trapped during sediment deposition. Subsequent isotopic changes may result from dilution by meteoric water, mixing of brines with contrasting chemical and isotopic compositions, or water-rock interaction. Oxygen and deuterium ratio values are important indicators for the origin of the water, whereas strontium (Sr) isotope ratios (87Sr/86Sr) can provide information on water mixing and migration, the extent and nature of water-rock interaction, and the chemical evolution of waters (Connolly and others, 1990); therefore, stable isotope geochemistry in combination with major-ion and trace-metal analysis seem to be promising geochemical tools to aid in the determination of the provenance of produced waters. Wittrup and Kyser (1990) sampled water from potash mineshafts in the northern Williston Basin in Saskatchewan at depths as great as 3,500 ft. Water from these samples was more representative of the formation than produced water, which has undergone chemical changes and possible mixing during translocation from the formation to the surface. The agreement in results between the Wittrup and Kyser (1990) study and a later study by Jensen and others (2006) indicate that the system has reached a dynamic equilibrium. Solute changes relative to depth are illustrated by the concentrations of TDS (fig. 57). The deepest samples in two mines evolved to calcium-chloride brines. In figure 58, the oxygen (δ18O) and hydrogen (δ2H) isotopic composition of the mineshaft water samples collected Mineshaft brines (Jensen and others, 2006) Depth, in feet below land surface Total dissolved-solids concentrations, in milligrams per liter 1,000 3,000 4,000 2,000 100,000 300,000 400,000 200,000 500,000 EXPLANATION Figure 57. Total dissolved solids in milligrams per liter relative to depth of mineshaft seeps of the northern Williston Basin, Saskatchewan, Canada (modified from Jensen and others, 2006). −160 −120 −100 −140 −80 −60 −40 −20
Global meteoric water line (Craig, 1961) −10 −15 −5 −20 Modern seawater (Hem, 1985) Bakken Formation produced-water sample (Boughton and others, 2022, table 4-2) Birdbear and Duperow Formations produced-water sample (Rostron and Arkadaksky, 2014) Mineshaft water sample (Wittrup and Kyser, 1990) EXPLANATION Hydrogen isotopic composition (δ2H), in parts per thousand Oxygen isotopic composition (δ18O), in parts per thousand Figure 58. Oxygen (δ18O) and hydrogen (δ2H) isotopic composition of modern seawater, produced-water samples from the Bakken, Birdbear, and Duperow Formations, and mineshaft water samples (Wittrup and Kyser, 1990; Rostron and Arkadakskiy, 2014).
Water-Use Data 103 by Wittrup and Kyser (1990) indicate mixing of meteoric water with water with δ18O and δ2H values similar to those of produced water from the Bakken, Birdbear, and Duperow For mations (fig. 2). Strontium (Sr) isotope ratios (87Sr/86Sr) also may be useful in constraining the origin of produced water in some areas (Banner, 2004). Brines with the greater δ18O and δ2H values may have formed by evaporation of seawater, which produces a curvilinear hook-like trend (Knauth, 1988; Connolly and others, 1990). Whatever the mode of formation, the δ18O and δ2H values, and 87Sr/86Sr ratios for brines from the Bakken and Upper Devonian sedimentary rocks may improve the understanding of the provenance of produced water. In the Williston Basin, many rocks are marine carbonates, evaporites, and clastic rocks (sandstones and shales). Carbon ate rocks acquire a marine 87Sr/86Sr ratio signature from seawa ter when they are deposited. The strontium isotopic variation in seawater during Phanerozoic time (about 541 million years to present [Cohen and others, 2019]) is well known (McAr thur and others, 2012). Formation water trapped in sediments will acquire the 87Sr/86Sr values of the host rocks by long-term water-rock interaction; thus, carbonate-hosted formation water is expected to carry strontium with an 87Sr/86Sr value close to marine values (fig. 59). Two groups of Poplar Dome brines mostly from the Mississippian Charles Formation were recognized based on major-ion and trace-metal chemistry and strontium isotopes (Peterman and Thamke, 2016) and are des ignated as group 1 and group 2. Group 1 brines are consistent with a long residency in carbonate rocks. Group 2 brines are associated with fluid production characterized by large waterto-oil ratios. Peterman and Thamke (2016) interpret these relations to have resulted from cross flow of formation water from younger stratigraphic units and mixing with group 1 brines. Figure 59 shows the strontium and 87Sr/86Sr values for the Poplar Dome samples in comparison with values from the Bakken Formation wells. Water-Use Data Water is a critical component needed to sustain life and is a finite resource. Its availability and use are codependent with the development of energy resources across the Nation. Water cannot be easily accessed by homes, businesses, and industries without delivery systems derived from the development of energy; likewise, most forms of energy development require variably scaled inputs of water to extract energy-rich materials like coal, natural gas, and petroleum. The United States faces two substantial and often competing challenges: (1) to provide sustainable supplies of freshwater for humans and ecosystems, and (2) to ensure adequate sources of energy are available for current and future generations (Healy and others, 2015). Issues associated with water and energy are multifaceted with many variables affecting their supply, demand, and manage ment. Water-resource managers are faced with complex issues because of the increasing demand placed on a small supply of water and energy resources. During the last 100 years, energy development in the upper Missouri River Basin, specifically in the Williston Basin, has expanded and contracted depending on develop ments in technology, availability of the energy resource, rising costs to develop and deliver the resource, energy market demands, and the dynamic political climate during the time of the resource's development. In the last decade, the Wil liston Basin has seen resurgence in unconventional oil and gas development—particularly with new technologies such as horizontal drilling and fracturing of oil-bearing strata with large quantities of water and other fluids. Energy resources in the Williston Basin have included finite resources such as coal (or lignite), oil and gas, and renewable resources like biofuels and wind (table 16). Each type of energy resource development, and the ancillary infra structure that helps support that type, has its own unique set of water requirements. Evaluation and quantification of surface-water and groundwater availability are needed to determine if the water sources can meet the needs of the energy development in an area. Two key components (or "metrics") to consider when evaluating water sources for any type of energy development are water withdrawals (and returns) and consumptive use. Withdrawals are water that is removed from a source and 10,000 1,000 Strontium, in milligrams per liter EXPLANATION Bakken Formation produced-water sample Poplar Dome produced-water sample, group 1 Poplar Dome produced-water sample, group 2 Strontium isotope ratio (87Sr/86Sr) Figure 59. Comparison of strontium (Sr) concentrations and isotope ratios (87Sr/86Sr) of produced water in the Poplar Dome of eastern Montana and the Bakken Formation of eastern Montana and North Dakota.
104 Potential Effects of Energy Development, Williston Basin—Water Resources Table 16. List of energy resources developed in the Williston Basin with U.S. energy consumption (in percent) for 2011 and 2014, and water-use requirements for each energy resource. less than] Resource sustainability Resource (fuel) type Resource material Development type Development process General water-use requirements for resource 2011/2014 U.S. energy consumption, in percent1,2 Nonrenewable Fossil Coal (including lignite) Conventional Surface/strip or under ground mining Coal washing to improve quality, dust abatement for mine roads, equipment maintenance, revegetation of surface mines, long-distance transport by coal slurry, and use in coal-fired powerplants (once-through and closed loop [or recirculating]/cooling ponds). 20.4/18.3 Nonrenewable Fossil Crude oil Conventional Primary recovery-vertical well Drilling, well completion, injection into the reservoir in secondary and enhanced oil recovery, and upgrading and refining into products. 36.2/35.4 Nonrenewable Fossil Crude oil Unconventional Primary recovery-vertical well, horizontal well, hydraulic fracturing Drilling, well completion and hydraulic fracturing, injection into the reservoir in secondary and enhanced oil recovery, oil and sands mining and in place recovery, and upgrade ing and refining into products. 36.2/35.4 Nonrenewable Fossil Natural gas Conventional Primary recovery-vertical well Drilling, well completion, injection into the reservoir in sec ondary and enhanced oil recovery, upgrading and refining into products. 25.5/27.9 Nonrenewable Fossil Natural gas Unconventional (including shale gas, coal bed meth ane, gas hydrates) Primary recovery-vertical well, horizontal well, hydraulic fracturing Drilling, well completion and hydraulic fracturing, injection into the reservoir in secondary and enhanced oil recovery, oil and sands mining and in place recovery, and upgrade ing and refining into products. 25.5/27.9 Renewable Hydro Water Conventional (dam and reservoir) Turbines Electricity generation, storage in a reservoir (for operating hydroelectric dams or energy storage), and discharge through water turbines in dam. 3/2.5 Renewable Biofuels Organic matter Conventional Crops (ethanol) Water-use requirements for crops and irrigation for feed stock crop growth, wet milling, washing and cooling in the fuel conversion process. 4.5/4.9 Renewable Wind Wind Conventional Windmills (wind farm) Minimal water usage unless in manufacturing of turbine parts in area. 1.5/1.7 Renewable Geothermal Geothermal Conventional Small scale-homes/schools Use in heating systems and maintenance. 0.22/0.22 Renewable Solar Solar Conventional Photovoltaics/concentrated solar power Use in manufacturing systems and maintenance. 1U.S. Energy Information Administration (2012a, table 1.3; 2014, table 1.3). 2Nuclear energy is not present in the Williston Basin; therefore, it is absent from this table. Because of this omission, the percentages do not total 100 percent.
Water-Use Data 105 may not be available for reuse, whereas a return is water that was initially unavailable and was returned to the source (may be near the withdrawal point or at a different location near the same source, or to a different source entirely). Returned water may have been treated before returning it to the source. Consumptive use is where the water is "consumed" or used and cannot be returned immediately to any source. These met rics can be used to develop an accurate water budget to fully understand the cycle of water use in an area and the effect that development of the energy resource's role has on that particu lar water budget. This is critical to determine if water needs for energy development can be met without compromising the water needs of others using the same water sources. Energy Development and Water Use Water is a key component in developing the mineralbased energy source. Uses of water in the development of the energy resource include but are not limited to (1) extraction of the raw material, (2) cleaning and processing the material, (3) use of the material in producing the energy, and (4) clean ing and disposing of residual waste from the generation of the energy. The amount of water needed for energy development is based on the type of raw material being used in producing the energy and the method used to generate the energy. The development of energy resources and associated water require ments in the Williston Basin differ with respect to the indi vidual States involved in developing the resource. Comparable energy and water-use data among States may not be available for every type of energy development discussed in this report. Coal Lignite coal was one of the first energy resources to be developed in the Williston Basin beginning when the first European settlers arrived in the area, and it continues to be one of the most used energy resources in the area today. Western North Dakota contains the single largest known deposit of lig nite in the world (Murphy, n.d.). Lignite is an inferior type of coal when compared to the higher quality coals like anthracite. Lignite is difficult to use because of its high water content (as much as 75 percent water in some varieties), weak cohesive ness, low heat value, and poor storage properties. Although all the lignite coal in North Dakota is low grade, it remains 1 of the 10 top coal-producing States in terms of total ton nage mined at about 30 million short-tons annually since 1988 (U.S. Energy Information Administration [EIA], 2008, 2009). Most users of lignite coal are thermoelectric powerplants and industries near mining sites in North Dakota. Lignite coal has been mined at hundreds of sites in North Dakota since the 1870s, but it is now recovered from only four surface mines in the west-central part of the State. Two smaller operations in the State mined oxidized lignite (leonardite), which is used in soil stabilization and as a drilling fluid additive (EIA, 2016b). Each of these mines is within the Williston Basin, and relies mostly on nearby surface-water features such as the Missouri River and, to a lesser extent, groundwater. These mines maintain water permits for surface water and groundwater that authorize withdrawals ranging from 50 to several hundred acre-ft per year (acre-ft/yr). Mines in this area typically use water for dust abatement (minimizing dust on nonpaved roads), cleaning and general maintenance of equipment, and to support use by employees. The lignite coal from North Dakota's four larger coal mines is used as fuel for steam boilers at electricity-generating plants in the State. Some of the State's powerplants also receive small amounts of coal from Montana and Wyoming. The Great Plains Synfuels Plant near Beulah, N. Dak., where lignite coal is converted into pipeline-quality synthetic natural gas (SNG) and a high purity carbon dioxide byproduct (EIA, 2016b), uses about 6 million tons of lignite coal on an annual basis from a nearby mine, surface water from Lake Sakakawea, and electric power from a nearby thermoelectric powerplant to produce 54 billion standard ft3 of SNG annually. The Synfuels plant has a 17,000 acre-ft/yr surface-water permit for obtaining water from Lake Sakakawea, about 10 mi away. Montana, with just six mines, produces more than 4 percent of coal in the United States. Most of Montana's coal production comes from several large surface mines in the Pow der River Basin in southeastern Montana (fig. 1). The Savage Mine, in the Williston Basin near the State line in northeastern Montana, delivers coal to a nearby thermoelectric powerplant (Lewis and Clark Power Station) southeast of Sidney, Mont., and to a sugar beet processing facility. The coal mine and powerplant are near the Yellowstone River. Similar to North Dakota, nearly all the coal extracted in the Williston Basin in Montana is used to generate electricity (EIA, 2016a). In contrast, South Dakota does not have any coal reserves in the Williston Basin. Coal brought into the State comes from Wyoming and is used for the generation of electricity. Also, South Dakota has no powerplants in the Williston Basin, but a small part of the coal delivered to South Dakota is used at industrial plants (EIA, 2016c). As a result, water used for energy development in South Dakota is minimal. Thermoelectric Powerplants Thermoelectric powerplants that consume coal substan tially affect water quantity and quality in the United States. According to the USGS, thermoelectric power is the largest user of water in the United States and accounted for 38 percent of the total freshwater withdrawals and about 91 percent of total saline-water withdrawals in 2010 (Maupin and oth ers, 2014). Water is used by thermoelectric powerplants to (1) extract, wash, and sometimes transport coal; (2) cool the steam used to make electricity in the powerplant; (3) control pollution from the plant; (4) mine and burn coal; and (5) pro cess waste byproducts. The cooling processes used in a coal-fired powerplant affect not only its water requirement but also the efficiency of the powerplant. While there are four cooling techniques
106 Potential Effects of Energy Development, Williston Basin—Water Resources used in thermoelectric power plants, the three major cooling processes utilized in the Williston Basin are (1) once-through, (2) wet-recirculating, and (3) dry cooling; each of these sys tems withdraw and consume water at different rates (table 17). Once-through cooling, also known as open-loop cooling, is the process where water is withdrawn from a source, circu lated through heat exchangers, and then returned to a body of water at a higher temperature. Wet-recirculating cooling, also Table 17. Water use for thermoelectric power cooling by type for conventional coal-fired powerplants in the Williston Basin, in gallons per megawatthour. Water use Withdrawal, in gallons per megawatthour Consumption, in gallons per megawatthour Once through1 20,000-50,000 100-317 Wet recirculating1 500-1,200 480-1,100 Dry cooling2 Limited Limited 1Data from Macknick and other (2012). 2Data from Electric Power Research Institute and California Energy Com mission (2002). known as closed-loop cooling, is the process where water is withdrawn from a source, circulated through heat exchangers, cooled, and then reused in the same process. The once-through cooling system withdraws substantially more water than the wet-recirculating process but has a lower consumption rate. Finally, dry cooling is the process of cooling using air rather than water, so this process uses considerably less water than the other processes. Dry cooling still requires water for system maintenance, cleaning, and blowdown (water intentionally wasted to avoid concentration of impurities during continu ing evaporation of steam) but uses approximately 95 percent less water than wet systems (Maulbetsch, 2004). On aver age, water-cooled thermoelectric powerplants in the Willis ton Basin withdraw less water than most other water-cooled powerplants in the United States in 2008 (fig. 60; Averyt and others, 2001). Currently, eight powerplants are operating in the Willis ton Basin: seven in four counties of North Dakota (McLean, Mercer, Morton, and Oliver), and one in Richland County, Montana (table 18). Four of the seven powerplants in North Dakota are considered once-through cooling plants, and the remaining three are wet-recirculating cooling plants. The total water permitted annually for coal-fired powerplants in North Dakota is about 1.8 million acre-ft. This includes withdrawn water (nonconsumed) and consumed water (Schuh, 2010). Less than 50,000 Less than 250,000 Less than 500,000 Less than 750,000 Withdrawals, in millions of gallons per year Cooling technology Once through Cooling pond Recirculating Dry cooled Less than 1,000,000 EXPLANATION Figure 60. Coal-fired powerplants and water withdrawals in million gallons per year by cooling technology, in the United States, 2008.
Water-Use Data 107 Table 18. Total self-supplied water withdrawals and power generated by thermoelectric powerplants for selected counties in North Dakota and Montana for 2005 and 2010. County (State) Total self-supplied withdrawals, in million gallons per day Power generated, in gigawatthours Total self-supplied withdrawals, total, in million gallons per day Power generated, in gigawatthours McLean (North Dakota) 8,708.89 8,699.71 Mercer (North Dakota) 15,725.65 14,680.05 Morton (North Dakota) Oliver (North Dakota) 5,117.83 4,535.30 Richland (Montana) Oil and Gas Like the development of coal, development of oil and gas resources in the Williston Basin has expanded and contracted depending on the economic market and political climate with the Williston Basin. The last substantial increase was in the late 1970s and early 1980s. In the early 2000s, a resurgence in oil production began, especially in the Bakken Formation. The resurgence may be attributed to new techniques in horizontal drilling and hydrofracturing, the refinement in oil and gas sup port technologies, higher oil prices, instability in the Middle East, and also in part to reevaluations of the assessment (oilbearing) units in the Williston Basin by the USGS and others. According to the North Dakota Department of Mineral Resources (EIA, 2012b), there were 4,141 wells in produc tion the North Dakota Bakken Formation in June 2012. The increasing number of oil rigs underscores the quickening pace of drilling in the area (table 19). Data from the North Dakota Oil and Gas Division indicate that in the Williston Basin, the mean weekly count of active horizontal-drilling rigs totaled 212 in June 2012. Of concern to water resources managers and others is the large amount of freshwater required to prepare a well for oil and gas production; in some cases, more than 3 to 7 million gallons (Mgal) for each well (Intermountain Oil and Gas BMP Project, 2015). Water is withdrawn from local aquifers, surface waters, or both, and then piped or trucked to the well pad. The withdrawal rate at many of these water sources often exceeds the sustainable recharge rate, particularly if the source is small. Additionally, freshwater supplies are potentially affected by post processing of produced waters through recycling, injec tion into waste wells, or processing at treatment plants for disposal of wastewater. The EPA estimates that hydraulic frac turing in the Williston Basin uses between 70 and 140 billion gallons (Bgal) of water in total each year (EPA, 2011). Water also is used for myriad purposes related to ancil lary oil and gas extraction. Some of the uses include (1) sup plemental fluid in enhanced recovery of petroleum resources; (2) drilling and completion of oil and gas wells; (3) work being done adjacent to or on an oil or gas well; (4) solution of underground salt in brine mining or hydrocarbon storage cav ern creation; (5) gas plant cooling and boiler water; (6) hydro static test water for pipelines and tanks; (7) rig and vehicle wash water; (8) coolant for internal combustion engines for rigs, compressors, and other equipment; and (9) sanitary and laboratory purposes. In addition to water used for immediate energy develop ment, the expanded human workforce migrating into the area and other support staff who have moved into the area during the development also use water. The increase in transient and permanent populations has stressed existing infrastructures in the area such that housing and utilities, including water use, are at risk of not being able to keep pace with rapidly expand ing needs associated with the development of the energy resources in the Williston Basin. Table 19. Active drilling rig counts for North Dakota, Montana, and South Dakota based on average count for January, 2005 to [Data from Baker Hughes Company (2016)] Year Active drilling rigs for the month of January North Dakota Montana South Dakota
108 Potential Effects of Energy Development, Williston Basin—Water Resources Hydropower The primary renewable source of power in the United States is hydropower. The USACE and the Bureau of Recla mation (Reclamation) are the largest producers of electricity from hydropower in the United States (Bureau of Reclama tion, 2015b). The USACE has been actively involved in build ing and operating hydroelectric plants since the 1930s. The USACE has six dams on the upper Missouri River of which three are in or adjacent to the Williston Basin. In contrast, Reclamation has no hydropower plants in the Williston Basin. The six USACE hydropower projects on the upper Mis souri River control runoff from about one-half of the Mis souri River Basin and comprise the largest system of dams and reservoirs in the United States. Three of the dams are in or adjacent to the Williston Basin and include Fort Peck Dam in eastern Montana, Garrison Dam in central North Dakota, and Oahe Dam in central South Dakota (fig. 17). These dams were authorized by Congress in the Flood Control Act of 1944 (commonly called the Pick-Sloan Act) and store Missouri River waters to provide flood control, irrigation development, navigation, municipal and industrial water supply, recreation, and hydropower generation (fig. 61). FORT PECK DAM GARRISON DAM OAHE DAM BIG BEND DAM GAVINS POINT DAM (25) (32) (31) (3) (8) (1) Storage, in percent of system total (73.4 MAF) FORT RANDALL DAM Cumulative storage, in percent of system total (73.4 MAF) (25) (57) (88) (91) (99) (100) 1,900 1,800 1,700 1,600 1,500 1,400 1,300 1,200 1,100 1,000 Distance, in miles above the mouth of the Mississippi River from St. Louis, Missouri (1960) FORT PECK DAM GARRISON DAM OAHE DAM BIG BEND DAM FORT RANDALL DAM Sioux City GAVINS POINT DAM 1,000 1,200 1,600 1,800 2,000 2,200 1,400 Elevation, in feet above mean sea level M O N T A N A N. D A K O T A N. D A K O T A S. D A K O T A S. D A K O T A N E B R A S K A [MAF, million acre-feet; N., North; S., South] EXPLANATION Gross storage, in mainstem reservoir system—Number indicates storage at the top of the exclusive flood control in MAF (U.S. Army Corps of Engineers, 1998, table 1) Exclusive flood control Annual flood control Carryover multiple use Permanent Top of the exclusive flood control, in feet above sea level— Would be full range of gross storage values (U.S. Army Corps of Engineers, 1998, table 1) Figure 61. Dams of the Missouri River main-stem system in downstream order according to river miles and the storage capacity of each dam and reservoir complex (U.S. Army Corps of Engineers, 1998, 2007).
Water-Use Data 109 The USACE operates the dams and reservoirs with the objective to balance water-use needs within the Missouri River Basin against natural hydrologic effects like precipita tion, runoff, and evaporation. Most of the annual water supply is produced by winter snows and spring and summer rains that increase Missouri River Basin storage. The highest mean power generation period extends from mid-April to mid-Octo ber, so high peak loads are during the winter heating season (mid-December to mid-February) and the summer air condi tioning season (mid-June to mid-August). During the spring and summer period, releases are intended mostly for naviga tion and flood control requirements and primary power loads are supplied using the four lower dams (USACE, 1998). The powerplants for the six dams generate a mean of 10.2 million megawatt hours (MWh) of energy annually, and Oahe and Garrison Dams (fig. 17) are typically the biggest power producers in the Missouri River system (USACE, 2006). Oahe and Garrison Dams annually generates 2.9 and 2.5 million MWh of energy, respectively (USACE, 2006). Biomass and Biofuels Energy from biomass and biofuels is derived from plant and animal materials that have been converted into a fuel. Bio mass can be broken down into two major fuel uses: (1) trans portation, and (2) electricity or heat (Healy and others, 2015). Wood is the most common biomass fuel and particularly is used for generating electricity or heat, but normally is not grown commercially as a fuel source. Other biogenic materi als that come from private industry, agriculture, or municipal processing also are used for making electricity and heat. Bio mass fuel production and use are not particularly large users of water compared to other technologies used to develop energy resources (National Research Council, 2008). The common biofuels ethanol and biodiesel are developed with their own water-usage requirements, which have increased substantially in the area. Water usage for the biofuels industry reflects a range of efficiencies based on the processes and methods used. Water-use estimates for the biofuels industry have generally decreased with time as water-use efficiency has improved. The processes involved in biofuel production are similar to those present in thermoelectric powerplants in that the largest use of water is for cooling (once-through, wet-recirculating, or dry-recirculating; Schuh, 2010). The amount of water used for each biofuel development is based on the fuel type and the conversion process used in production (table 20). Biofuel energy development has been on the rise in North Dakota (Great Plains Energy Corridor, 2014a). According to the NDSWC, there have been six ethanol- and two biodieselproducing plants in operation in North Dakota. Two ethanol plants are within the Williston Basin; one receives Missouri River water from a regional water supplier and the other is co-located with one of the thermoelectric powerplants on the Missouri River. Additionally, there are four facilities currently being considered for development. Based on the current water usage in existing ethanol plants, total water use from cur rent and future ethanol plants would be between 5,600 and 6,500 acre-ft/yr. The only biodiesel plant within the Williston Basin is in north-central North Dakota. The plant uses ground water, and annual water use is less than 300 acre-ft (Schuh, 2010). Montana and South Dakota have no biomass or biofuel plants within the Williston Basin. Wind The development of wind as an energy resource has become one of the most economical renewable energy tech nologies. Its effects on local or regional water sources are limited to manufacturing of wind technology components and the effect of wind turbine placement on the local environment. According to the January 2012 report of the American Wind Energy Association, North Dakota is ranked 6th in the United States for available wind resources (Piehl, 2013). Table 20. National water-use summary estimates for biofuels production. [Data from National Research Council (2008, table 4). approximately; less than] Fuel type Conversion process Processing water-use intensity, in gallons of water per gallon of fuel Feedstock water-use intensity Process water use Process water consumption Feedstock water demand, in acre-feet per acre Feedstock water consumption, in gallons of water per gallon of fuel Ethanol (starch or sugar based) Wet or dry mill
~1.0 to 2.3 980-1,360 Ethanol (cellulose based) Biochemical or ther mochemical ~2.3 to 2.5 Rain-fed Biodiesel (oil extraction) Transesterification
6,100-not determined
110 Potential Effects of Energy Development, Williston Basin—Water Resources According to Piehl (2013), the January 2012 report (could not be located) indicated the North Dakota Public Service Commission had issued permits or received letters of intent for more than 6,000 megawatts of additional wind project development in addition to the almost 1,000 wind turbines and projects operating in the State. Most of these projects are in the central one-third of the State and at the southeastern edge of the Williston Basin. The wind turbines do not need water once they are constructed; any water use by a wind company would be for employee use, sanitation, and cleaning. North Dakota has four manufacturing facilities in operation. These facilities are in the eastern one-half of North Dakota and not within the Williston Basin. In 2015, Montana ranked 22nd for installed wind capac ity with 479 wind turbines, and South Dakota ranked 19th for installed wind capacity with 583 wind turbines and 5 manufacturing facilities (American Wind Energy Association, 2015a, b). The wind manufacturing facilities are in the eastern part of South Dakota, and not within the Williston Basin (American Wind Energy Association, 2015b). Geothermal Geothermal energy uses heat from the Earth to either heat or cool a structure based on the outside ambient air tempera ture. Geothermal energy can be drawn from several sources that include the following: (1) hot water or steam reservoirs deep in the Earth that are accessed by drilling, (2) geothermal reservoirs near the Earth's surface (mostly in the western part of the United States), and (3) shallow groundwater near the Earth's surface that maintains a nearly constant temperature of 50 to 60 degrees Fahrenheit (°F) (National Renewable Energy Laboratory, 2016). The amount of water needed is determined by the type of geothermal process used in a system and how much consumptive use, if any, happens within the system over time. The development of large-scale geothermal energy in the Williston Basin is nonexistent. Montana has 15 geothermal sites identified for possible development but none within the Williston Basin. Large-scale geothermal energy sites need to be in areas where geothermal activity is present, such as Yel lowstone National Park (National Resources Defense Council, 2016). Similarly, North Dakota and South Dakota have no major geothermal energy developments, just small geother mal heat exchangers used in domestic and a few commercial settings. Future studies may develop ways to use byproducts from oil and gas development in the western part of North Dakota in geothermal processes. It is interesting to note that the North Dakota Geological Survey does produce geothermal maps for the State of North Dakota (North Dakota Geological Survey, 2016). Solar Solar energy use is on the rise in the United States according to the Solar Energy Industries Association (2016). The increase in solar development is a result of advance ment in technologies and a reduction in costs associated with solar development. There are two main types of solar energy technology: (1) photovoltaics (PV) use the Sun's rays to create direct current electricity from solar cells, and (2) concentrated solar power uses mirrors typically to concentrate the Sun's rays and create heat that drives turbines. Solar energy in the Williston Basin is limited to domestic uses such as solar pan els on homes. No major solar energy development has been done in the Williston Basin, and data on water usage for solar energy development are nonexistent. An example of industrial/commercial uses of solar energy exist in North Dakota is Verendrye Electric Cooperative (Great Plains Energy Corridor, 2014b). Verendrye Electric Coop erative in north-central North Dakota has the largest solar operation in North Dakota. The cooperative uses more than 240 solar-run water pumps in a six-County area around Minot, N. Dak., to supply water for livestock in remote areas where building power lines are cost prohibitive. In North Dakota, a water permit is not required for watering livestock, so it is difficult to determine the effect these solar pumps have on the local water sources. State Water-Use Regulations and Permitting Legislation As energy development, particularly for unconventional oil and gas, expands in the Williston Basin, so do regulations governing the industry with its ancillary infrastructures. In addition, uncertainty exists as to jurisdictions over the water resources (water rights) that often span National, State, local government, private, and Tribal borders. Water rights are legal entitlements authorizing water to be diverted from a specified source and put to beneficial, nonwasteful use. Water rights guarantee the holder of the access to the water in question; however, the holder does not own the water itself, only the right to use it, and often with restrictions. Many States view the waters within a State as belonging to the "people of the State" so that all people living in the State can, at some time, use that water. Some States require a permit or license from a State water regulatory agency whose objective is to ensure the State's waters are put to the best possible use, and that the public interest concerning water usage is served. When allocating water rights, a State water regulatory agency must consider developing the water resources in an orderly manner, preventing waste and unrea sonable use of water, ensuring water availability in times of stressed conditions (for example, drought), and protecting the environments associated with the water resources.
Water-Use Data 111 In the United States, there are two doctrines of water appropriation recognized by the States: (1) riparian and (2) prior appropriation. Riparian doctrine allows property owners to use water that is adjacent to their property, often like a property right. The prior appropriation doctrine evolved wherein the first user (senior) of water from a specific water source had highest senior legal right to continue to use the water. Most States in the eastern and southeastern part of the United States adhere to the riparian doctrine where the climate generally makes water more readily available. Some States in the Midwest and the western part of the United States, where the climate is more arid, follow the prior appropriation doc trine because water, usually from a sustainable source, often has to be diverted some distance before it is used. Information and web links for surface-water and ground water withdrawal laws and regulations (including the doctrine of appropriation, administering agency, criteria to consider when determining an individual water right, water withdrawal permit and application requirements, State water withdrawal fees, water withdrawal statutes and administrative codes, and links to other State-specific water withdrawal resources) for North Dakota, Montana, and South Dakota were obtained from the States. Each State has its own methods of regulating and reporting water usage within its jurisdiction. These meth ods can introduce problems when examining water use from sources, such as the Missouri River or Fox Hills aquifer (part of Upper Cretaceous aquifer system), that are shared across political boundaries. Without the one-to-one match for usage types and amounts used from a water source, it is difficult to develop a comprehensive water budget for the water source being evaluated. North Dakota In North Dakota, a permit is required for any surface or groundwater withdrawal, except those for which the amount used is less than 12.5 acre-ft/yr, and the use is for domestic, livestock, fish, wildlife, or recreation (North Dakota Legislative Branch, 2013b). The following questions are considered when a new appropriation of water is requested in North Dakota: Is the use beneficial? Is the amount requested reasonable? What are previous uses for the source? Can all uses be sustained from the source? What are the effects? Permitted withdrawals must be reported annually on individual response forms. Reports indicating unreasonable amounts of use for a given category or amounts exceeding the permitted amount are investigated by the office of the State Water Engineer. Also, during periods of water stress (for example, droughts), the State has the authority to temporary ily suspend or amend the permits to the stressed source. The permitting of water in the State of North Dakota is administered by the NDSWC according to the authority and guidelines con tained in the following references: North Dakota Legislative Branch (2013b) North Dakota State Water Commission (2015a, 2015b) Montana In Montana, a new surface-water or groundwater with drawal requires the filing of an Application for Beneficial Water Use Permit with the Department of Natural Resources and Conservation, Water Resources Bureau. Any new sur face-water withdrawal must be permitted with the exception of small livestock pits. Permits for groundwater withdrawal are required only for withdrawals in excess of 35 gallons per minute (gal/min). The following questions are considered when a new appropriation of water is requested in Montana: Is the use beneficial? Is the amount requested reasonable? What are previous uses for the source? Can all uses be sustained from the source? What are the effects? If the application is approved, the applicant receives a permit. Once a permit is received, the permittee then must construct the project, divert the water, and put the water to the intended use as outlined in the permit. The permitting of water in the State of Montana is administered by the Montana Division of Natural Resources and Conservation, Division of Water Resources according to the authority and guidelines contained in the following references: Montana Department of Natural Resources and Con servation (2016) Montana Legislature (2011) Administrative Code: Water Resources Bureau New Appropriation Rules (Mont. Admin. R. 36.12.101.2001 [2005]) ://www.mtrules.org/gateway/ruleno. asp?RN=36%2E12%2E2001 Legislative Environmental Quality Council (2008) South Dakota In South Dakota, all surface and groundwater withdraw als require a water right permit, except for domestic water uses and water distribution systems that do not pump more than 18 gal/min. The following criteria are considered when a new appropriation of water is requested in South Dakota: (1) if water use requested is available, (2) is the water use beneficial, and (3) the potential for the proposed water use to impair other water rights.
112 Potential Effects of Energy Development, Williston Basin—Water Resources After approval of a water right permit, the permit owner has 5 years to complete any construction. The owner then has an additional 4 years to put the water to beneficial use. A water right permit may be amended to extend the time for comple tion of construction, or the time may be extended to put the water to beneficial use. Once approved and water is being applied to beneficial use, changes may be made under auspices of the Chief Engineer of the Water Rights Program. Tempo rary water permits may be issued by the Chief Engineer when small amounts of public water are needed on a temporary basis. The permitting of water in the State of South Dakota is administered by the SDDENR according to the authority and guidelines contained in the following references: South Dakota water laws and rules (SDDENR, 2001, 2016a, b) South Dakota Legislature (1987) South Dakota water rights application (SDDENR, 2016c) Research and Information Needs The primary objective of this reporting activity is to characterize the water resources near areas of energy devel opment in the Williston Basin. A secondary objective is the identification of research and information needs that could be relevant in the evaluation of the effects of energy development on water resources. The following summarizes the informa tion and research needs identified during the aggregation and characterization of the scientific information related to ground water, streams and rivers, water quality, produced water, and water use in the Williston Basin. Groundwater Resources Information needs identified during a study of groundwa ter availability in the lower Tertiary/Upper Cretaceous units include (1) the need for improved potentiometric surface maps for glacial units, (2) the availability of a uniform stream net work digital geographic coverage that spans the international boundary with Canada, and (3) enhanced surface-water use information with regards to the gain and loss of streamflow to shallow groundwater, which would increase understanding of groundwater and surface-water interactions. In addition, there are large gaps between smaller areas within the Williston Basin and energy productions areas where geophysical data have been collected. With the exception of the East Poplar oil field study (Thamke and Craigg, 1997; Smith and others, 2006a, b, 2014; Thamke and Smith, 2014), there is a lack of borehole geophysical logging data to tie to specific hydro geologic settings (lithologies and water chemistry). Though airborne and ground-based geophysical surveys have been used in the East Poplar oil field study and several other energy production areas of the United States, there has been no sys tematic coverage throughout the Williston Basin, particularly those areas developed for unconventional resources. Prioritiza tion of sites for integrating geophysical, hydrologic, and eco system studies can be done in terms of areas of high risk (Pres ton and Chesley-Preston, 2015) or high vulnerability (Preston and others, 2014a, b), such as those identified in the "Lake and Wetland Resources" section of this report. In addition to these general priorities, land-use managers have specific, site-scale, high priority issues (Farag and Harper, 2014) such as design of remediation for accidents that release saline waters on the landscape. Airborne and ground-based geophysical surveys can provide unique and critical subsurface information needed to understand site- and landscape-scale processes related to salinization of ecosystems by natural and anthropogenic processes. River and Stream Resources Ice-jam flooding continues to be a problem within the Williston Basin, as evidenced by oil or gas well flooding (with associated leakage of oil from damaged wells) on the Mis souri River downstream from the confluence with the Yel lowstone River in 2014 (Associated Press, 2014). The USGS has published peak-flow frequency analyses for streamgages in the Williston Basin (Williams-Sether, 1992; Sando and others, 2008, 2016); however, ice-jam conditions can result in annual peak stages that are substantially higher than the stages associated with annual peak flows. The USGS has not pub lished peak-stage frequency analyses for streamgages in the Williston Basin. The USGS NWIS database contains annual peak-flow data and annual peak-stage data. Detailed analysis and description of annual peak flow and annual peak stage relations for streamgages in the Williston Basin might provide valuable information to assist in better understanding icejam issues; furthermore, publication of peak-stage frequency analyses for streamgages in the Williston Basin might assist in structure design activities in the Williston Basin. In much of the Williston Basin, there are numerous stock dams and diversion dams, and the cumulative effect of these small impoundments on streamflow is understood poorly; fur thermore, the locations and characteristics of most of the small dams are not documented in existing datasets. In responding to spills or leakage of oil or produced water, knowledge of the presence and characteristics of small dams could be important in evaluating potential effects on surface-water and groundwa ter resources. With advancements in remote-sensing technolo gies, it might be feasible to complete remote-sensing analysis of aerial photography or satellite imagery to produce a dataset that documents locations and characteristics of small dams in the Williston Basin.
Research and Information Needs 113 Quality of Water Resources Consistent with findings from Bowen and others (2015), the information provided in this report identifies substan tial limitations of the available data to answer water-quality questions related to unconventional oil and gas development in the Williston Basin. Water-quality data collected specifi cally for energy development investigations are scarce, and a national water-quality monitoring program focused on energy development does not exist. The number of small-scale waterquality studies with data specific to energy development is sparse. A groundwater-quality study, specifically of the Upper Fort Union aquifer, was completed by the USGS in 2014 (McMahon and others, 2014). Results indicated that there was no evidence that energy-development activities affected groundwater quality; however, it is important to consider these results in the context of groundwater age. Most samples were recharged before the early 1950s and had carbon-14 ages rang ing from less than 1,000 to greater than 30,000 years; thus, the wells sampled in the McMahon and others (2014) study may not be as well suited for detecting contamination associated with surface spills as compared to shallower wells screened near the water table. Although the deeper aquifers remain an important potential source of water, and monitoring of these resources should continue, future studies focusing primarily on shallower groundwater sources, such as the Quaternary unconsolidated aquifer system and surface-water systems, may better characterize potential effects of unconventional oil and gas development. Additional water-quality data are collected by energy development companies, but generally the data are proprietary and not accessible to the public. The large water-quality dataset in this report presented several challenges that limit the ability to characterize the status of water quality in the Williston Basin. Challenges with the dataset include duplicate sites from multiple agencies, varied sample collection protocols and analytical methods, differing levels of data-quality reviews, and variations in the reporting processes from the collecting agencies and analyti cal laboratories. The reported constituent results may not always be reviewed by agencies before entry in the WQP, potentially resulting in errors in reporting and thus contribut ing to the wide range of reported concentrations. The large range in concentrations also may be attributed to variations in sample design for several of the independent studies. Waterquality data collected for specific studies (for example, studies of water-quality during or after storm events, or in areas of known water-quality issues) may target water-quality constitu ents not commonly associated with energy development. Specific gaps in the water-quality dataset for the Williston Basin that have been identified include the following: Few water-quality sampling sites in the Montana and South Dakota parts of the Williston Basin. Insufficient data on effects of energy development on Lake Sakakawea. Insufficient long-term data required for completing trend analyses. Insufficient evaluation of groundwater depths for iden tifying aquifer units. A complete evaluation of all constituents was beyond the scope for this study. Additional analyses that would help better plan and inform future research needs include the following: Evaluating sites monitored after unconventional oil and gas development for differences in water quality based on their distance from oil and gas wells (less than 1 kilometer compared to more than 1 kilometer). Comparing groundwater and surface-water quality samples collected from sites near oil and gas wells before and after unconventional oil and gas develop ment. Identifying sites and constituents that have enough data to complete trend analyses. Comparing trends between sites near and not near oil and gas wells. Evaluating water samples with oxygen and sulfate data as a rough indicator of samples that are methanogenic. Coordination between agencies (State, Tribal, and Federal) and private industry concerning monitoring could improve the design of future assessments of water quality and may reduce overall sampling costs. This coordination could focus on improving cooperative approaches to reduce redun dancy in sampling programs and develop a consistent design (sampling and analytical methods) for long-term water-quality assessments. The types of water-quality data included in the assessments could be evaluated to ensure the collection of the supplemental data needed in the Williston Basin. Several con siderations for coordinated agency (State, Tribal, and Federal) and private industry water-quality sampling programs for the Williston Basin include the following: Designing an efficient Williston Basin water-quality sampling program that requires spatial and temporal components to minimize redundancy. Using a systematic approach to identify specific con stituents that could be monitored in areas of unconven tional oil and gas development, similar to the approach documented by Olsen and others (2013). Constituents that could be considered include boron, chloride, bromide, iodine, fluoride, manganese, lithium, radium, strontium isotopes, volatile organic compounds, and isotopes of inorganic ions (such as hydrogen and car bon). Identifying consistent sampling locations for groundwa ter, streams and rivers, and lakes and reservoirs to gen erate data to evaluate future water-quality conditions, including comparisons against historical samples.
114 Potential Effects of Energy Development, Williston Basin—Water Resources Focusing studies on shallower groundwater sources, such as the Quaternary aquifers, and surface-water sys tems to better characterize potential effects of uncon ventional oil and gas development. Deeper aquifers remain an important potential resource and should be monitored as well. Installing continuous water-quality monitors to poten tially determine spills on a real-time basis. Produced Water Although the USGS NPWGD is valued as a source of geochemical data for produced waters within the Williston Basin, Blondes and others (2014) have described the limita tions, uncertainties, and considerations associated with these data. Specifically, much of the information in the database cannot be independently verified because methods of col lection, sample preservation, chemical analysis, assignment of geologic units, and record keeping were not standardized or have changed with time. It also is important to note that minimum reporting levels and quality-assurance information are typically lacking. The distribution and amount of water produced among geologic units may not be represented fully by the samples in the NPWGD. Data collected in the past may not resemble current production because of water flooding, recompletion in other intervals, and workovers within the well. Although criteria were applied to remove the questionable samples, the culling of unrepresentative data is considered preliminary. It is important to note that the wealth of information available through the NPWGD provides an opportunity for further data mining activities. Although the NPWGD has limitations and missing data, there are opportunities for further analysis to examine site-specific, temporal evaluations of data. Detailed records could be retrieved from the Oil and Gas Information system database (Montana Board of Oil and Gas Conservation, 2015), the North Dakota Industrial Commis sion (2015), Department of Mineral Resources, Oil and Gas Division (Oil and Gas Division, 2015), and possibly private industry. Further work could be done to compare not only the geochemistry among units, but also the spatial variation of geochemistry within those units. In addition, data could be evaluated to examine chemistry at individual drill sites within sampled geologic units. Although the USGS has previously examined areas of horizontal drilling combined with hydraulic fracturing of shale gas, the USGS has completed little work in areas of tightoil reservoirs, such as the Bakken Formation; consequently, there are opportunities for more complete characterization of the quality and quantity of produced waters in the area. The chemical and isotopic composition of produced waters can be further developed to characterize the range of chemi cal, microbial, and isotopic compositions and quantities of "end-member" produced waters. The chemical and isotopic characterization of produced water from all hydrocarbon reservoirs is needed to assess the potential mixing of produced waters with the freshwater (surface-water and groundwater) resources of an area. In addition, little work has been done to characterize hydraulic fracturing fluids and flowback waters from samples collected immediately after hydraulic fracturing followed by samples collected at fixed numbers of days after hydraulic fracturing. Future sample collection, chemical analy sis, and interpretation of produced-water chemistry within the Williston Basin would complement the USGS NPWGD and previously acquired data from oil-production wells by the USGS. Water-Use Data The effects of rapid development of new oil and gas resources, and the associated infrastructure, during the last decade on water sources in the upper Missouri River Basin, specifically in the Williston Basin, have caused concerns among government agencies, resource managers, environ mentalists, Tribal groups, and the public. Long-term energy development requires sources of high-quality, sustainable, or renewable water supplies, and updated information about water use associated with oil and gas development in the upper Missouri River Basin. To assess the feasibility and desirabil ity of several management options for water resources of the upper Missouri River Basin, an improved understanding of water use is needed to provide a reliable resource from which to make the best management decisions in the future. Detailed information about water use in the Williston Basin is scant. The Williston Basin spans several political boundaries, and within the boundaries are a variety of regu latory and monitoring controls on water so that water-use data reporting is not seamless across the span of the area; for example, the database FracFocus is a hydraulic fracturing chemical registry website designed to provide information about chemicals and some water used in the hydraulic fractur ing of oil and gas wells (Ground Water Protection Council and the Interstate Oil and Gas Compact Commission, 2010). The database is maintained and hosted by the Ground Water Protection Council (://www..org/) and the Interstate Oil and Gas Compact Commission (://iogcc.publishpath. com/). The FracFocus website provides a means for indus try to voluntarily supply hydraulic fracturing chemical data and some water data in a consistent and centralized location. Because the data are voluntarily submitted by industry and the States have differing reporting requirements, FracFocus' use has to be reviewed on a State-by-State basis rather than by a region or basin that extends beyond State boundaries. A study of water use with data on withdrawals and returns from water users in the Williston Basin, and investigations of trends in the overall water usage in the Williston Basin area with respect to the ongoing energy development, was published by McShane and others (2020).
Summary 115 Although the power sector is responsible for the high est withdrawal volumes of water in the Nation, and certainly within the Williston Basin, statistics on the consumption and withdrawal rates of individual powerplants are inconsistent and scarce (U.S. Government Accountability Office, 2015). Power sector water-use data are collected by State and Federal agencies that may not always use the same methods or defini tions in determining water withdrawals (Kenny and others, 2009). Data are not comprehensive and may not contain infor mation on nuclear facilities and some natural gas combinedcycle technologies (EIA, 2015). Additionally, the quality of data is of concern because many powerplants report water withdrawal and consumption values that are considerably less or greater than values cited in general studies of water use in powerplants. The National Energy Technology Laboratory compiled water use data in their 2007 Coal Power Plant Data Base; however, these data are limited by the availability and quality of EIA information. A similar public database has not been developed for natural gas or nuclear power-generating facilities (Macknick and others, 2012). Water permitting and monitoring for energy development differs by State. One State may require reporting of annual water use as a requirement for keeping a water permit active, whereas another State may not require any annual reporting in the same industry. Lack of compatible water-use data in all sectors of energy development make it difficult to determine the adequacy of water resources for developing and maintain ing energy development and for looking at long-term trends. Summary The Williston Basin has been a leading domestic oil and gas producing area for more than 50 years. While oil produc tion initially peaked within the Williston Basin in the mid1980s, production rapidly increased in the mid-2000s, largely because of improved horizontal (directional) drilling and hydraulic fracturing methods. The improvement in extraction methods made oil and gas resources in low-permeability sand stones and shales, or "tight-oil" formations such as the Bakken and Three Forks Formations, accessible. In 2012, energy development associated with the Bakken Formation was identified as a priority requiring collaboration toward improved timeliness of issuing permits for new wells combined with reasonable measures to maintain environmen tal quality. Shortly thereafter, the Bakken Federal Executive Group was created to address common challenges associated with energy development. The Bakken Federal Executive Group partner agencies identified a gap in current understand ing of the cumulative environmental challenges attributed to energy development throughout the area, resulting in an effort to aggregate scientific data, and identify areas of additional research and information needs related to natural resources within areas of energy development in the Williston Basin. As part of this effort, water resources in the area, including groundwater; streams and rivers; and lakes, reservoirs, and wetlands, were characterized and described in terms of physi cal presence, flow characteristics, recharge, water quality, and water use. Waters produced during energy-development activities also were discussed even though these waters are not considered usable resources of the area. Groundwater Resources Three major hydrogeologic units, the glacial, lower Tertiary, and Upper Cretaceous aquifer systems, supply most of the groundwater used for domestic, stock, agricultural, and industrial purposes. The glacial aquifer system overlies parts of the lower Tertiary and Upper Cretaceous aquifer systems in the northeastern part of the Williston Basin. The glacial aquifer system is highly variable, with multiple, disconnected, but locally productive sand and gravel deposits in the Willis ton Basin, that are sources of water for thousands of shallow wells. The lower Tertiary aquifer system consists of the upper and lower Fort Union aquifers separated by the middle Fort Union hydrogeologic unit. The upper Fort Union aquifer is present in Montana and North Dakota and is the most used aquifer of the lower Tertiary aquifer system. Because of vari able lithology, the middle Fort Union hydrogeologic unit may act as a confining unit or as an aquifer in parts of the Williston Basin. The Upper Cretaceous aquifer system is the deepest and most spatially extensive of the major hydrogeologic units underlying the Williston Basin. The Upper Cretaceous aquifer system consists of the upper Hell Creek hydrogeologic unit, lower Hell Creek aquifer, and Fox Hills aquifer, all of which are present throughout most of the Williston Basin. Although the lower Hell Creek and Fox Hills aquifers are sources of water in much of the Williston Basin, the upper Hell Creek hydrogeologic unit may act as a confining unit in some areas and as an aquifer in other areas. Groundwater recharge to the glacial, lower Tertiary, and Upper Cretaceous aquifer systems is from stream infiltration, precipitation, and irrigation, and discharge from these aqui fer systems is primarily as groundwater discharge to streams (base flow) and reservoirs, but also is due to withdrawals from wells for domestic, irrigation, public-supply, and self-supplied industrial uses. Water in the lower Tertiary and Upper Creta ceous aquifer systems primarily is under confined conditions. Where aquifers in the lower Tertiary and Upper Cretaceous aquifer system are covered by the glacial aquifer system or unconsolidated alluvial deposits, water can percolate down ward through these deposits to the bedrock aquifers. South of the glacial aquifer system where the upper Fort Union aquifer is unconfined, localized groundwater flows from topographi cally high areas toward stream valleys. In the other lower Ter tiary and Upper Cretaceous hydrogeologic units, groundwater flow generally is from the west and southwest toward the east, with regional discharge to streams. Potentiometric surfaces for the upper Fort Union and lower Fort Union aquifers are simi lar in the northern and western parts of the Williston Basin,
116 Potential Effects of Energy Development, Williston Basin—Water Resources except for less relief for the lower Fort Union aquifer, indicat ing probable hydraulic connection between the two aquifers. In addition to describing groundwater resources for the three major hydrogeologic units, this report included informa tion on the deeper Lower Cretaceous and upper and lower Paleozoic aquifers/aquifer systems. These aquifers/aquifer systems are used rarely and mainly are undeveloped in most of the Williston Basin because of uneconomical drilling depths, poor groundwater quality unsuitable for most uses without treatment, or both; however, within the Williston Basin these units are used or may have potential use as water supplies if treated, reservoirs for injection of produced waters or other anthropogenic wastes, or sources of mineral and energy resources. River and Stream Resources The Williston Basin is within two major river systems— about 86 percent of the Williston Basin is in the Missouri River system, and about 12 percent is in the Hudson Bay system. The remaining 2 percent is in the Devils Lake closed basin. Within the Williston Basin, 360 U.S. Geological Survey (USGS) streamgages have 10 or more years of data collection through water year 2014, and 194 of the 360 have year-round or seasonal continuous streamflow data to produce daily streamflow records and also annual peak-flow records that rep resent the maximum instantaneous discharge for each year of a streamgage's operation. The length of data collection for the 194 streamgages ranges from 10 to 112 years, with a median of about 25 years. A substantial part of the Missouri River Basin upstream from the Williston Basin (hereinafter referred to as the "upstream Missouri River Basin") is mountainous, with about 31 percent of the drainage area being higher than 6,000 feet in elevation. Much of the streamflow generated in the upstream Missouri River Basin results from high-elevation snowmelt that typically is in May and June; however, the upstream Missouri River Basin is somewhat strongly regu lated, with four major reservoirs with multipurpose operations that includes flood control; the four reservoirs individually have total storage capacities that exceed 325,000 acre-feet and cumulatively have about 4,300,000 acre-feet of total storage capacity. Similar to the upstream Missouri River Basin, much of the streamflow generated in the upstream Yellowstone River Basin results from high-elevation snowmelt that typically occurs in May and June; however, the upstream Yellowstone River Basin has substantially less major regulation than the upstream Missouri River Basin, with a single major reservoir with multipurpose operations that include flood control. Streamflow characteristics were described for 17 streamgages in Williston Basin that had greater than 50 years of data collection from water years 1954 through 2014. The selected streamgages were classified as representing either major rivers (the Missouri or the Yellowstone Rivers, with a substantial part of the drainage basin outside the Wil liston Basin) or large streams (drainage basins from 551 to 22,452 square miles, most of which is within the Williston Basin). Monthly and annual streamflow characteristics were calculated to look at seasonal and interannual variability in streamflow and provide general information on primary driv ers of streamflow and reliability of streamflow on seasonal and multiple-year scales. Daily-streamflow and annual-extremeflow characteristics were calculated to provide information on short-term and extreme streamflow conditions, such as floods or zero-streamflow conditions that happen within short periods. Short-term streamflow statistics provide hydrologic information that might be relevant to infrastructure design and also evaluating potential causes and environmental effects of accidental spills, leaks, or discharges of water or products to the system. Streamflows for the streamgages on the Missouri River, generally displayed large effects of regulation as evidenced by generally small seasonal and interannual variability in stream flows. Differences in the timing of annual peak flows between Missouri River stations primarily reflect tributary inflows; however, most of the Missouri River streamflow is generated upstream from the Williston Basin, and streamflow inputs gen erally are small in the reach from below Fort Peck Dam to the confluence with the Yellowstone River. Streamflows for the Yellowstone River sites reflected a high-elevation-snowmelt dominated hydrologic regime within a large predominantly unregulated drainage basin. The snowmelt-dominated hydro logic regime is evidenced by somewhat large seasonal vari ability in streamflows, but generally small interannual (yearto-year) variability in streamflows. Similar to the Missouri River, most of the Yellowstone River streamflow is generated upstream from the Williston Basin, and streamflow inputs are small within the Williston Basin. In general, streamflow characteristics of large streams originating in or near the Williston Basin are driven by com plex interactions between climatic, geologic, topographic, and land-cover and use characteristics, and interactions of ground water and surface water. Anthropogenic activities, including reservoir and irrigation operations, also contribute to stream flow variability. Streams in the Williston Basin generally have large seasonal and interannual variability in streamflows. Large-scale spatial differences in streamflow characteristics are substantially affected by spatial variability in precipitation, air temperature, and drainage characteristics (especially the density of depressional storage or percent of area covered by lakes and wetlands). Variability in snowpack accumulation in relation to the frequency and intensity of spring and summer rainfall contributes to differences in seasonal streamflow char acteristics among streams. Lakes and Wetland Resources State-wide National Wetlands Inventory datasets were acquired for Montana, North Dakota, and South Dakota on March 16, 2015, and used to classify lake, wetlands, and other surface-water features other than streams and rivers. A
Summary 117 total of 1,428,501 National Wetlands Inventory palustrine and lacustrine features were identified using the Cowardin system within the Williston Basin, and these features were combined to produce estimates of the numbers of features for four clas sifications: other, wetland, pond, and lake, which are collec tively referred to as surface-water features. Spatial distribution information, specifically number, area, and percent coverage of National Wetlands Inventory features, were calculated for the Williston Basin, the area inside and outside of the multiState Prairie Pothole Region, and each State and county. The surface-water feature dataset also was analyzed in relation to the State-maintained oil or gas well databases to investigate the proximity of surface-water features to energy-related wells. Proximity analyses to determine the number, area, and percent of surface-water features within 0.4, 0.8, and 1.6 kilo meter (km) of at least one oil or gas well were completed for the Williston Basin, the area inside and outside of the Prairie Pothole Region, and each State and county. Within the Williston Basin, the total number, area, and percent coverage of surface-water features are greater in the Prairie Pothole Region than the area outside of the region; for example, the Prairie Pothole Region covers only 28.9 percent of the Williston Basin yet contains three times the number of surface-water features as the area outside the region. Despite having nearly three-quarters of all surface-water features within the Williston Basin, the area of surface-water fea tures in the Prairie Pothole Region is only 1.2 times greater than the area of surface-water features outside the region, mainly because several large lakes along the Missouri River exist outside the region. Finally, the percent of the landscape covered by surface-water features is 2.9 times greater within the Prairie Pothole Region compared to the area outside the region. The spatial distribution of surface-water features also varied among Montana, North Dakota, and South Dakota and varied among individual counties within the Williston Basin. Although the area of North Dakota in the Williston Basin is only 1.4 times larger than Montana, North Dakota has more than 6.5 times as many surface-water features. Similarly, the area of North Dakota in the Williston Basin is only 2.7 times greater than South Dakota, yet it has 16.6 times as many surface-water features. Across the Williston Basin, most oil or gas wells (98.7 percent) are within 1.6 km of surface-water features, whereas most surface-water features (69.6 percent) were not proximate to oil or gas wells; however, this number will likely decrease with expected future development. While many sur face-water features are proximate to only one oil or gas well, some surface-water features are proximate to numerous oil or gas wells and some oil or gas wells are proximate to numerous surface-water features. The proximity of surface-water features to oil or gas wells in the Williston Basin was different inside and outside the Prairie Pothole Region. The Prairie Pothole Region covers only 28.9 percent of the Williston Basin and contains only 29.1 percent of the total identified oil or gas wells; however, the Prairie Pothole Region contains about three times as many surface-water features proximate to oil or gas wells in all three buffer distances (0.4, 0.8, and 1.6 km) as compared to the area outside the Prairie Pothole Region. The proximity of surfacewater features to oil or gas wells also varied among States and among individual counties within the Williston Basin. North Dakota has about 2.1 and 24.7 times as many oil or gas wells as Montana and South Dakota, respectively; however, it also has 6.5 and 16.6 times as many surface-water features, respec tively. Additionally, the total number and area of surface-water features proximate to oil or gas wells in North Dakota are much greater than Montana and South Dakota in all three buf fer distances. Similarly, Montana has a much greater num ber of oil or gas wells and surface-water features compared to South Dakota and, therefore, a greater total number and area of surface-water features proximate to oil or gas wells. Notably, the percentage of surface-water features proximate to oil or gas wells in all three buffer distances was highest in Montana, followed by North Dakota and South Dakota. Quality of Water Resources Water-quality data were aggregated from two data sources: (1) the Water-Quality Portal, sponsored by the USGS, U.S. Environmental Protection Agency (EPA), and National Water Quality Monitoring Council; and (2) a data compila tion completed as part of the USGS National Water-Quality Assessment project. The Water-Quality Portal integrates publicly available water-quality data from databases main tained by the USGS, EPA, and U.S. Department of Agricul ture, including water-quality data from Tribal, State, and local databases. Water-quality data for 15 commonly measured water-quality constituents were aggregated for groundwater, rivers and streams, and lakes and reservoirs. For each aggre gated dataset (groundwater, rivers and streams, and lakes and reservoirs), analyses of the water-quality data included summary statistics, maps of spatial distribution of constitu ent values, boxplots of constituent values by timeframe or hydrogeologic unit, spatial comparisons of site locations and constituent values to petroleum well density, and comparisons of the constituent values measured to EPA drinking-water standards/guidelines. Produced Water Produced water includes all fluids brought to the surface along with the targeted hydrocarbons as part of the oil and gas exploration and extraction processes. These fluids may include formation water (waters that co-exist with rock/oil/gas), hydraulic fracturing fluids, and other combinations of water and chemicals used during oil and gas well drilling, develop ment, treatments, recompletions, and workovers. Produced water datasets were aggregated from two sources: the USGS National Produced Waters Geochemical database (ver. 2.1) and a series of projects focused specifically on sampling produced water in the Williston Basin from 2010 to 2014.
118 Potential Effects of Energy Development, Williston Basin—Water Resources The National Produced Waters Geochemical database was useful for a general understanding of produced-water chem istry. Produced waters are characterized by extreme salinity and contain elevated concentrations of other constituents (including arsenic, barium, cadmium, lead, zinc, radium-226/ radium-228, and ammonium) that could negatively affect water and aquatic resources if released. Produced waters also have a generally unique chemical (isotopic) signature that may be useful in tracking water from different geologic units; for example, the oxygen/deuterium and strontium ratio values measured in brine waters from the Bakken Formation are distinct from brines collected from other geologic units in the Williston Basin. Water-Use Data Water-use information related to energy production in the area was aggregated and summarized. The summary of water use is not limited to oil and gas production but includes water used to produce all types of energy resources in the Williston Basin, including coal/lignite, thermoelectric power, oil and gas, hydropower, biomass and biofuels, wind, geothermal, and solar. Each State has its own methods for regulating and reporting water usage within its jurisdiction. These methods can introduce problems when examining water use from sources, such as the Missouri River or Fox Hills aquifer, that are shared across political boundaries. Without the one-to-one match for usage types and amounts used from a water source, it is difficult to develop a comprehensive water budget for the water source being evaluated. A large amount of freshwater is required to prepare a well for oil and gas well production; in some cases, 3 to 7 million gallons of water are needed per well. The EPA estimates that hydraulic fracturing in the Williston Basin uses between 70 to 140 billion gallons per year. Water also is used for myriad other purposes related to ancillary oil and gas extraction. In addition to water used for immediate energy development, the expanded human work force migrating into the area and other support staff who have moved into the area during the development also use water. Research and Information Needs Research and information needs were identified that could be relevant in the evaluation of the effects of energy development on water resources. Information needs related to the evaluation of groundwater resources include the follow ing: improved potentiometric-surface maps for glacial units; availability of a uniform stream network digital geographic coverage that spans the international boundary with Canada; enhanced surface-water use information with regards to the gain and loss of streamflow to shallow groundwater, which would increase understanding groundwater and surface-water interactions; and expanded geophysical assessments. Gaps in the availability of streamflow data include the lack of infor mation on ice-jam flooding despite potential for effects to infrastructure (pipelines, roads, and facilities) and an under standing of the cumulative effects of largely undocumented stock and diversion dams. Although this study resulted in the aggregation of a large quantity of water-quality data, the avail ability of consistently collected, systematically processed and reported data over large parts of the Williston Basin is sparse. Few samples have been analyzed for constituents that may indicate the effect of energy development on water resources. Constituents that could be considered include boron, chloride, bromide, iodine, fluoride, manganese, lithium, radium, stron tium isotopes, volatile organic compounds, and isotopes of inorganic ions (such as hydrogen and carbon). Collaboration between Tribal, Federal, State, and local entities to identify a common study design, common monitoring constituents, and consistent sampling locations would generate datasets with broad utility and would likely result in overall cost savings for monitoring over time. Similarly, there is a need for standard ized sample collection, processing, laboratory analytical methods, and the collection of ancillary data for produced waters sampling. Additional characterization of the range of chemical, microbial, and isotopic compositions and quantities of "end-member" produced waters, and the collection of timeseries datasets to document the changes in produced waters during and after well development also were needs identified during this study. Water-use estimates would be improved through the implementation of comprehensive studies of water use from groundwater and surface-water sources using consis tent methodologies across the Williston Basin. The submission of chemical and water data related to hydraulic fracturing col lected by the oil and gas industry would add to the quantity of available data. Consistent implementation of regulations and monitoring controls across political boundaries (State, county, and international) would further improve the consistency of data available for the estimates of water use. References Cited Alkalali, A., 2002, Petroleum hydrogeology of the Nisku aquifer: Edmonton, Alberta, Canada, University of Alberta, Department of Earth and Atmospheric Sciences, M.S. the sis, 152 p. American Wind Energy Association, 2016a, Montana wind energy: American Wind Energy Association, accessed August 19, 2021, at ://climatenexus.org/wp-content/ uploads/2015/09/Montana.pdf. American Wind Energy Association, 2016b, South Dakota wind energy: American Wind Energy Association, accessed August 19, 2021, at ://climatenexus.org/wp-content/ uploads/2015/09/South-Dakota.pdf.
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References Cited 131 U.S. Geological Survey [USGS], 2015c, USGS water data for the nation: U.S. Geological Survey, National Water Infor mation System, digital data, accessed September 29, 2015, at ://doi.org/10.5066/F7P55KJN. U.S. Geological Survey [USGS] and the American Association of State Geologists, 2012, National Geologic Map Data base: U.S. Geological Survey and the American Association of State Geologists, digital data, accessed June 25, 2015, at ://.usgs.gov/Geolex/search. U.S. Government Accountability Office, 2015, Technology assessment—Water in the energy sector—Reducing fresh water use in hydraulic fracturing and thermoelectric power plant cooling: U.S. Government Accountability Office, GAO-15-545, 107 p. Veil, J.A., Puder, M.G., Elcock, D., and Redweik, R.J., Jr., 2004, A white paper describing produced water from production of crude oil, natural gas, and coal bed methane: U.S. Department of Energy, Argonne National Laboratory, 87 p., accessed October 6, 2016, at ://www.circleofblue. org/wp-content/uploads/2010/08/prodwaterpaper1.pdf. Vuke, S.M., Porter, K.W., Lonn, J.D., and Lopez, D.A., 2007, Geologic map of Montana: Montana Bureau of Mines and Geology Geologic Map 62C, 73 p., 2 sheets, scale 1:500,000. Wartman, B.L., 1984, Geology and hydrology of the Inyan Kara Formation (Lower Cretaceous), North Dakota, in Jorgensen, D.G., and Signor, D.C., eds., Geohydrology of the Dakota aquifer—Proceedings of the First C.V. Theis Conference on Geohydrology, Lincoln, Nebr., October 5-6, 1982: Worthington, Ohio, The National Water Well Associa tion, p. 22-25. White, K.D., and Zufelt, J.E., 1994, Ice jam data collection: U.S. Army Cold Regions Research and Engineering Labora tory, Special Report 94-7, 45 p. accessed March 1, 2019, at ://rivergages.mvr.usace.army.mil/WaterControl/ Districts/MVP/Reports/ice/docs/SR94_07.pdf. Whitehead, R.L., 1996, Ground water atlas of the United States—Segment 8, Montana, North Dakota, South Dakota, Wyoming: U.S. Geological Survey Hydrologic Atlas 730-I, 24 p. [Also available at ://pubs.usgs.gov/ha/730i/report. pdf.] Whittaker, S.G., Christopher, J.E., Gilboy, C.F., Haidl, F.M., Kent, D.M., Kreis, L.K., and Thomas, P., 2002, Geological storage of greenhouse gases in Mississippian carbonates at the Weyburn field, in Summary of investigations 2002: Sas katchewan Geological Survey, Saskatchewan Industry and Resources, Miscellaneous Report 2002, v. 4.1, p. 73-82. Whittaker, S.G., and Gilboy, C.F., 2003, IEA Weyburn CO2 monitoring and storage project—Geoscience framework update, in Summary of investigations 2003: Saskatchewan Geological Survey, Saskatchewan Industry and Resources, Miscellaneous Report 2003, v. 4.1, Paper A-7, 9 p. Whittaker, S.G., Rostron, B.J., Khan, D., Hajnal, Z., Qing, H., Penner, L., Maathuis, H., and Goussev, S., 2004, Theme 1— Geological characterization, in Wilson, M., and Monea, M., eds., IEA-GHG Weyburn CO2 monitoring and storage proj ect summary report 2000-2004: International Conference on Greenhouse Gas Control Technologies, 7th, Petroleum Technology Research Center, 2004, v. 3, p. 15-69. Williams-Sether, T., 1992, Techniques for estimating peakflow frequency relations for North Dakota streams: U.S. Geological Survey Water-Resources Investigations Report 92-4020, 57 p. Winter, T.C., Benson, R.D., Engberg, R.A., Wiche, G.J., Emer son, D.G., Crosby, O.A., and Miller, J.E., 1984, Synopsis of ground-water and surface-water resources of North Dakota: U.S. Geological Survey Open-File Report 84-732, 127 p. [Also available at ://pubs.er.usgs.gov/publication/ ofr84732.] Wittrup, M.B., and Kyser, T.K., 1990, The petrogenesis of brines in Devonian potash deposits of western Canada: Chemical Geology, v. 82, p. 103-128. Woods, A.J., Omernik, J.M., Nesser, J.A., Shelden, J., Comstock, J.A., and Azevedo, S.H., 2002, Ecoregions of Montana (2d ed.), color poster with map, descriptive text, summary tables, and photographs, scale 1:1,500,000.
Appendix C1 Within the Williston Basin, 360 U.S. Geological Survey streamgages have 10 or more years of data collection through water year 2014. The locations and summary information for these streamgages are presented in figure 1-1 and table 1-1. Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014. The following list of tables are included in the associated data release (Boughton and others, 2022) and are provided here as an aid to readers: Table 1-2. Summary statistics for monthly and annual streamflows at selected streamgages. Table 1-3. Summary statistics for annual extreme flows at selected streamgages. Table 2-1. Total number of surface-water features not including streams and rivers for the portions of the 71 counties of Montana, North Dakota, and South Dakota located wholly or partially within the Williston Basin. Table 2-2. Area of surface-water features not including streams and rivers for the portions of the 71 counties of Montana, North Dakota, and South Dakota located wholly or partially within the Williston Basin. Table 2-3. Percent coverage of surface-water features not including streams and rivers for the portions of the 71 counties of Montana, North Dakota, and South Dakota located wholly or partially within the Williston Basin. Table 2-4. Number of surface-water features not including streams and rivers located within 0.4, 0.8, and 1.6 kilometers of at least one oil well within the portions of the 71 counties of Montana, North Dakota, and South Dakota located wholly or partially within the Williston Basin. Table 2-5. Area of surface-water features not including streams and rivers located within 0.4, 0.8, and 1.6 kilometers of at least one oil well within the portions of the 71 counties of Montana, North Dakota, and South Dakota located wholly or partially within the Williston Basin. Table 2-6. Percent of surface-water features not including streams and rivers located within 0.4, 0.8, and 1.6 kilometers of at least one oil well within the portions of the 71 counties of Montana, North Dakota, and South Dakota located wholly or partially within the Williston Basin. Table 3-1. Summary of constituents analyzed in groundwater regardless of constituent fraction type and units reported. Table 3-2. Summary of constituents analyzed in streams and rivers regardless of constituent fraction type and units reported. Table 3-3. Summary of constituents analyzed in lakes and reservoirs regardless of constituent fraction type and units reported. Table 3-4. Aquifers sampled in the Williston Basin. Table 3-5. Groundwater sites sampled for at least one of the five commonly monitored parameters during 1970 through 2014 and collecting agencies. Table 3-6. Summary of stream and river sites in the Williston Basin that had ten or more samples of at least one of the five primary parameters during 1970 through 2014 and collecting agencies. Table 3-7. Lake and reservoir sites in the Williston Basin that had samples of at least one of the five primary parameters during 1970 through 2014 and collecting agencies. Table 3-8. Summary statistics for specific conductance in groundwater in the Williston Basin from 1970 through 2014. Table 3-9. Summary statistics for total dissolved solids in groundwater in the Williston Basin from 1970 through 2014. Table 3-10. Summary statistics for pH in groundwater in the Williston Basin from 1970 through 2014. Table 3-11. Summary statistics for sulfate in groundwater in the Williston Basin from 1970 through 2014. Table 3-12. Summary statistics for chloride in groundwater in the Williston Basin from 1970 through 2014. Table 3-13. Summary statistics for selected trace metals in groundwater in Quaternary aquifers in the Williston Basin for samples analyzed during 1993 through 2014. Table 3-14. Summary statistics for selected trace metals in groundwater in lower Tertiary aquifers in the Williston Basin for samples analyzed during 1993 through 2014. Appendix C1 133
134 Potential Effects of Energy Development, Williston Basin—Water Resources Table 3-15. Summary statistics for selected trace metals in groundwater in Upper Cretaceous aquifers in the Williston Basin for samples analyzed during 1993 through 2014. Table 3-16. Summary statistics for specific conductance at selected stream and river sites in the Williston Basin from 1970 through 2014. Table 3-17. Summary statistics for total dissolved solids at selected stream and river sites in the Williston Basin from 1970 through 2014. Table 3-18. Summary statistics for pH at selected stream and river sites in the Williston Basin from 1970 through 2014. Table 3-19. Summary statistics for sulfate at selected stream and river sites in the Williston Basin from 1970 through 2014. Table 3-20. Summary statistics for chloride at selected stream and river sites in the Williston Basin from 1970 through 2014. Table 3-21. Summary statistics for selected trace metals in streams and rivers in the Williston Basin at sites that had 10 or more samples analyzed during 1993 through 2014. Table 3-22. Summary statistics for specific conductance at selected lake sites in the Williston Basin from 1970 through 2014. Table 3-23. Summary statistics for total dissolved at selected lake sites in the Williston Basin from 1970 through 2014. Table 3-24. Summary statistics for pH at selected lake sites in the Williston Basin from 1970 through 2014. Table 3-25. Summary statistics for sulfate at selected lake sites in the Williston Basin from 1970 through 2014. Table 3-26. Summary statistics for chloride at selected lake sites in the Williston Basin from 1970 through 2014. Table 3-27. Summary statistics for specific conductance at selected sites on Lake Sakakawea, North Dakota from 1993 through 2014. Table 3-28. Summary statistics for total dissolved solids at selected sites on Lake Sakakawea, North Dakota from 1993 through 2014. Table 3-29. Summary statistics for pH at selected sites on Lake Sakakawea, North Dakota from 1993 through 2014. Table 3-30. Summary statistics for sulfate at selected sites on Lake Sakakawea, North Dakota from 1993 through 2014. Table 3-31. Summary statistics for chloride at selected sites on Lake Sakakawea, North Dakota from 1993 through 2014. Table 3-32. Summary statistics for selected trace metal data in lakes and reservoirs in the Williston Basin at sites that had 10 or more samples analyzed during 1993 through 2014. Table 4-1. Geochemical data retrieved from the U.S. Geological Survey National Produced Waters Geochemical Database v.2.1. Table 4-2. Chemistry of produced waters from Bakken and Three Forks Formation oil-production wells sampled by the U.S. Geological Survey, Montana and North Dakota, 2012-2014.
Appendix C1 135 itt e
M isso u ri River Poplar River Lake Oahe Fort Peck Lake Musselshell River Bighorn River Powder River Y ellow stone Rive r
S ou r s
Ri e r
Mi ss ou ri R e r
Mi ss ou ri R e r Sheyenne River Milk River # # # ## # # # ## # # # # # # ## # # # # # ## # # ## # # # # # # # # # ## # # # # # # # # # # # ## ### ### # # # # # # # # # # ## # # ## # # ## # ## # # # # # # # ### # # ### # # # # # # # # # # # # # ### ## # ## # # ## # # # # # ## # # ## # # ## # # # # # # # # # ### # # # # # ### ## # # ### # # # # # # # ## ## # ## # ## # # # ## # # # # # # # # # ## # # # # # # # ## # ## # # # # ### ## # # # # ## # # # # # # # # ### # # # # # # # # # # # # # ## # # # # ## # # # # # ## # ## # # # # # ## # # # ## # # # # ## # # # # # # ## # # # # # ## # 100° 105° 110° 48° 45° MONTANA WYOMING NORTH DAKOTA SOUTH DAKOTA EXPLANATION UNITED STATES CANADA MILES KILOMETERS Williston Basin boundary Bakken Formation boundary # U.S. Geological Survey streamgage and identifier (table 1-1) Base map modified from U.S. Geological Survey, Esri, and Commission for Environmental Cooperation digital data variously dated, various scales. Base map image is the intellectual property of Esri and is used herein under license. Copyright © 2014 Esri and its licensors. All rights reserved. Albers Equal-Area Conic projection, standard parallels 29°30' N. and 45°30' N., central meridian 96°00' W. North American Datum of 1983 Figure 1-1. U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.
136 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014. [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Sheyenne River above Harvey, ND −99.9490 Sheyenne River near Harvey, ND −99.8907 North Fork Sheyenne River near Wellsburg, ND −99.7185 Big Coulee near Maddock, ND −99.5801 Sheyenne River above Devils Lake State Outlet near Flora, ND −99.4156 1,661 Sheyenne River below Devils Lake State Outlet near Bremen, ND −99.2761 1,716 Sheyenne River at Sheyenne, ND −99.1251 1,790 Big Coulee near Fort Totten, ND −98.9676 Sheyenne River near Warwick, ND −98.7162 2,070 Mauvais Coulee Tributary near Bisbee, ND −99.3865 Mauvais Coulee Tributary No. 3 near Cando, ND −99.2243 Mauvais Coulee Tributary No. 4 near Bisbee, ND −99.4476 Little Coulee at Leeds, ND −99.4490 Little Coulee near Leeds, ND −99.3729 Little Coulee near Brinsmade, ND −99.2432
Appendix C1 137 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Big Coulee near Churchs Ferry, ND −99.2212 1,620 1,462 Channel A near Penn, ND −98.9801 Long Creek Tributary No. 2 near Crosby, ND −103.3163 Long Creek near Crosby, ND −103.2682 2,080 Long Creek Tributary near Crosby, ND −103.3224 Long Creek near Noonan, ND −103.0766 1,790 Souris River near Sherwood, ND −101.9582 8,940 3,040 Souris River near Foxholm, ND −101.5054 9,470 3,270 Souris River Tributary near Burlington, ND −101.4207 Tasker Coulee Tributary near Kenaston, ND −102.1254 Des Lacs River Tributary near Donnybrook, ND −101.8560 Des Lacs River at Foxholm, ND −101.5702 Fuller Coulee at Foxholm, ND −101.5671 Souris River Tributary No. 2 near Burlington, ND −101.3804 Souris River above Minot, ND −101.3713 10,600 3,900 Bonnes coulee near Velva, ND −100.9504
138 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Souris River near Verendrye, ND −100.7296 11,300 4,400 Wintering River Tributary near Kongsberg, ND −100.7596 Wintering River near Bergen, ND −100.6713 Wintering River near Karlsruhe, ND −100.5399 Souris River West Outfall at Eaton Dam near Towner −100.4928 Souris River East Outfall at Eaton Dam near Towner −100.4881 Souris River near Bantry, ND −100.4349 12,300 4,700 Willow Creek at Dunseith, ND −100.0629 Oak Creek at Lake Meti gosh Outlet near Bot tineau, ND −100.3635 Oak Creek Tributary near Bottineau, ND −100.4110 Oak Creek Tributary No. 5 near Bottineau, ND −100.3454 Willow Creek near Willow City, ND −100.4421 1,160 Deep River near Upham, ND −100.8626 Egg Creek near Glenburn, ND −101.4046 Egg Creek near Ruthville, ND −101.2990
Appendix C1 139 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Egg Creek Tributary near Deering, ND −101.1532 Egg Creek near Deering, ND −101.1227 Egg Creek near Granville, ND −100.8224 Cut Bank Creek at North Lake Outlet near Granville, ND −100.7671 Cut Bank Creek at Upham, ND −100.7446 Boundary Creek near Landa, ND −100.8632 Souris River near Westhope, ND −100.9585 16,900 6,600 Bair Coulee near Mosby, MT −107.6126 Sand Creek near Jordan, MT −106.8490 Second Creek Tributary near Jordan, MT −106.8024 Second Creek Tributary No. 2 near Jordan, MT −106.8162 Second Creek Tributary No. 3 near Jordan, MT −106.8260 Russian Coulee near Jordan, MT −106.7114 Thompson Creek Tributary near Cohagen, MT −106.4613 Spring Creek Tributary near Van Norman, MT −106.3062 Little Dry Creek near Van Norman, MT −106.3636 1,223
140 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Big Dry Creek near Van Norman, MT −106.3578 2,551 Terry Coulee near Van Norman, MT −106.1708 Nelson Creek near Van Norman, MT −106.1535 Mcguire Creek Tributary near Van Norman, MT −106.1530 Missouri River below Fort Peck Dam, MT −106.3563 56,490 Milk River at Eastern Crossing of international boundary −110.4218 2,496 Spring Coulee Tributary near Simpson, MT −110.2160 Sage Creek Tributary No. 2 near Joplin, MT −110.7730 Woodpile Coulee near inter national boundary −109.5311 East Fork Battle Creek near international boundary −109.1303 Battle Creek near Chinook, MT −109.2317 1,631 1,485 Fifteenmile Creek Tributary near Zurich, MT −109.0457 Milk River near Harlem, MT −108.7590 9,652 9,184 Fifteenmile Creek Tributary near Harlem, MT −108.7083 Peoples Creek near Hays, MT −108.7141
Appendix C1 141 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Willow Coulee near Dodson, MT −108.4154 Peoples Creek near Dodson, MT −108.3598 Kuhr Coulee Tributary near Dodson, MT −108.3887 Peoples Creek below Kuhr Coulee near Dodson, MT −108.3562 Milk River near Dodson, MT −108.2941 11,134 10,666 Alkali Creek near Malta, MT −107.9662 Disjardin Coulee near Malta, MT −107.9643 Taylor Coulee near Malta, MT −107.9147 Milk River at Malta, MT −107.8629 11,654 11,186 Murphy Coulee Tributary near Hogeland, MT −108.7479 Milk River at Cree Crossing near Saco, MT −107.5199 13,134 12,560 Whitewater Creek near inter national boundary −107.8622 Lush Coulee near Whitewater, MT −107.6910 Milk River at Juneberg Bridge near Saco, MT −107.2188 17,691 17,117 Beaver Creek above Dix Creek near Malta, MT −107.5555 Guston Coulee near Malta, MT −107.5486
142 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Beaver Creek below Guston Coulee near Saco, MT −107.5822 1,199 Beaver Creek near Hinsdale, MT −107.1711 1,805 1,678 Rock Creek at international boundary −106.7923 Horse Creek at international boundary −106.8352 Rock Creek below Horse Creek near international boundary −106.8398 McEachern Creek at international boundary −106.9285 Willow Creek near Hinsdale, MT −106.9825 Rock Creek near Hinsdale, MT −107.0365 1,300 Milk River near Vandalia, MT −106.9732 21,052 20,351 Buggy Creek near Tampico, MT −106.7779 Unger Creek near Vandalia, MT −106.7974 Milk River at Tampico, MT −106.8223 21,341 20,640 Mooney Coulee near Tampico, MT −106.7092 Willow Creek Tributary near Fort Peck, MT −106.8903 Willow Creek near Glasgow, MT −106.6716
Appendix C1 143 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Milk River Tributary No. 3 near Glasgow MT −106.5523 Milk River at Nashua, MT −106.3643 22,452 20,254 Snow Coulee at Opheim, MT −106.4137 Porcupine Creek at Nashua, MT −106.3423 Prairie Elk Creek near Oswego, MT −105.8674 East Fork Sand Creek near Vida, MT −105.6143 East Fork Wolf Creek near Lustre, MT −105.7941 Wolf Creek Tributary No. 2 near Wolf Point, MT −105.7538 Wolf Creek near Wolf Point, MT −105.6802 Missouri River No. 6 near Wolf Point, MT −105.5569 Missouri River near Wolf Point, MT −105.5331 80,647 Tule Creek Tributary near Wolf Point, MT −105.4927 East Fork Duck Creek near Brockway, MT −105.7856 Duck Creek near Brockway, MT −105.8171 Redwater River at Brock way, MT −105.7677 Tusler Creek near Brockway, MT −105.6635
144 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Tusler Creek Tributary near Brockway, MT −105.6785 Redwater River Tributary Brockway, MT −105.6850 South Fork Dry Ash Creek near Circle, MT −105.5973 McCune Creek near Circle, MT −105.5860 Redwater River at Circle, MT −105.5756 Cow Creek Tributary near Vida, MT −105.4945 West Fork Sullivan Creek near Richey, MT −105.2351 Gady Coulee near Vida, MT −105.4971 Horse Creek Tributary near Richey, MT −104.9359 Redwater River near Vida, MT −105.2128 1,982 Poplar River at international boundary −105.6969 Butte Creek Tributary near Four Buttes, MT −105.5861 West Fork Poplar River near Richland, MT −106.0212 Poplar River near Bredette, MT −105.2101 2,921 Poplar River near Poplar, MT −105.1786 3,140
Appendix C1 145 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Missouri River Tributary No. 2 near Brockton, MT −104.9019 Big Muddy Creek at Daleview, MT −104.9391 Middle Fork Big Muddy Creek near Flaxville, MT −105.1139 Big Muddy Creek at Plentywood, MT −104.5781 Box Elder Creek near Plentywood, MT −104.4997 Marron Creek Tributary near Plentywood, MT −104.4551 Spring Creek at Highway near Plentywood, MT −104.5252 Big Muddy Creek near Antelope, MT −104.5121 Big Muddy Creek diversion canal near Medicine Lake, MT −104.5490 Lake Creek near Dagmar, MT −104.1776 Cottonwood Creek near Dagmar, MT −104.1734 Sand Creek near Dagmar, MT −104.2726 Lost Creek Tributary near Homestead, MT −104.4975 Big Muddy Creek near Culbertson, MT −104.7236 2,670
146 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Big Muddy Creek Tributary near Culbertson, MT −104.6979 Big Muddy Creek near mouth near Culbertson, MT −104.6295 2,37 Missouri River Tributary No. 3 near Culbertson, MT −104.5158 Missouri River Tributary No. 4 near Bainville, MT −104.3528 Missouri River Tributary No. 5 at Culbertson, MT −104.5161 Missouri River near Culbertson, MT −104.4733 89,959 89,858 Rock Springs Creek Tribu tary at Rock Springs, MT −106.2544 Deep Creek near Kinsey, MT −105.6207 Cut Coulee near Mizpah, MT −105.1687 Mizpah Creek near Mizpah, MT −105.2934 Meyers Creek near Locate, MT −105.2789 Powder River near Locate, MT −105.3103 13,060 Locate Creek Tributary near Locate, MT −105.1819 Cherry Creek Tributary near Terry, MT −105.3412 Lame Jones Creek Tributary near Willard, MT −104.5522
Appendix C1 147 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year O'Fallon Creek near Ismay, MT −104.7610 O'Fallon Creek Tributary near Ismay, MT −104.7424 Deep Creek near Baker, MT −104.3010 Pennel Creek Tributary near Baker, MT −104.2394 Yellowstone River Tributary No. 4 near Fallon, MT −105.1018 Spring Creek Tributary near Fallon, MT −104.9911 Yellowstone River Tributary No. 5 near Marsh, MT −104.8985 Timber Fork Up Sevenmile Creek Tributary near Lindsay, MT −105.1727 Cains Coulee at Glendive, MT −104.7133 Yellowstone River at Glendive, MT −104.7203 66,731 66,039 South Fork Horse Creek Tributary near Wibaux, MT −104.3810 Griffith Creek near Glendive, MT −104.5618 Griffith Creek Tributary near Glendive, MT −104.5973 Krug Creek Tributary No. 2 near Wibaux, MT −104.3060
148 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Yellowstone River Tributary No. 6 near Glendive, MT −104.6546 Thirteenmile Creek Tributary near Bloomfield, MT −104.8316 Linden Creek at Intake, MT −104.5258 Indian Creek at Intake, MT −104.5405 War Dance Creek near Intake, MT −104.4883 Burns Creek near Savage, MT −104.4300 Alkali Creek near Sidney, MT −104.1178 Yellowstone River near Sidney, MT −104.1554 69,099 68,407 Fox Creek Tributary near Lambert, MT −104.6149 First Hay Creek near Sidney, MT −104.2748 Charbonneau Creek near Charbonneau, ND −103.7941 Painted Woods Creek Tribu tary near Williston, ND −103.8838 Painted Woods Creek near Williston, ND −103.8685 Painted Woods Creek Tribu tary No. 2 near Williston, ND −103.8199 Missouri River near Wil liston, ND −103.7146 164,500 Sand Creek at Williston, ND −103.6533
Appendix C1 149 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Little Muddy River below Cow Creek near Williston, ND −103.5730 Little Muddy Creek near Williston, ND −103.5972 White Earth River Tributary near Tioga, ND −102.9060 White Earth River at White Earth, ND −102.7672 White Earth River Tributary near White Earth, ND −102.7532 Bear Den Creek near Mandaree, ND −102.7685 Shell Creek near Parshall, ND −102.1366 East Fork Shell Creek near Parshall, ND −102.2149 Deepwater Creek at Mouth near Raub, ND −102.1077 Little Missouri River at Camp Crook, SD −103.9712 1,974 1,974 Coal Creek Tributary near Mill Iron, MT −104.3619 Box Elder Creek at Webster, MT −104.0576 1,097 North Fork Coal Bank Creek Mill Iron, MT −104.0928 Soda Creek Tributary near Webster, MT −104.0935
150 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Little Beaver Creek near Marmarth, ND −103.9763 Little Missouri River at Marmarth, ND −103.9175 4,640 Deep Creek near Bowman, ND −103.3685 Little Missouri River at Medora, ND −103.5282 6,190 Sheep Creek Tributary near Medora, ND −103.4485 Sheep Creek Tributary 2 near Medora, ND −103.4735 Little Missouri River Tribu tary near Medora, ND −103.5060 Jules Creek near Medora, ND −103.4874 Spring Creek near Wibaux, MT −104.2004 Beaver Creek at Wibaux, MT −104.1838 Beaver Creek near Trotters, ND −103.9927 Little Missouri River Tribu tary near Watford City, ND −103.2785 Little Missouri River near Watford City, ND −103.2519 8,310 8,310 Cherry Creek Tributary near Arnegard, ND −103.3694 Spring Creek near Watford City, ND −103.2652
Appendix C1 151 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Missouri River near Elbowoods, ND −102.2005 179,800 East Branch Douglas Creek Tributary near Garrison, ND −101.5196 Snake Creek Tributary near Garrison, ND −101.3521 Missouri River at Garrison Dam, ND −101.4310 181,400 181,400 Missouri River below Garrison Dam, ND −101.3938 181,400 Knife River at Manning, ND −102.7699 Knife River at Marshall, ND −102.3338 Elm Creek near Golden Valley, ND −102.0518 Knife River near Golden Valley, ND −102.0599 1,230 Brush Creek near Beulah, ND −101.7852 North Creek near Werner, ND −102.5032 Spring Creek at Zap, ND −101.9257 West Branch Otter Creek near Beulah, ND −101.6602 Knife River at Hazen, ND −101.6221 2,240 2,240 West Branch Antelope Creek No. 4 near Zap, ND −101.8549 Coal Lake Coulee near Hensler, ND −101.1315
152 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Turtle Creek near Turtle Lake, ND −100.9213 Turtle Creek above Washburn, ND −100.9124 Painted Woods Creek near Wilton, ND −100.7921 Square Butte Creek at Cen ter, ND −101.2990 Square Butte Creek Tributary No. 2 near Center, ND −101.2518 Square Butte Creek Tributary near Center, ND −101.2588 Square Butte Creek Tributary No. 3 near Center, ND −101.1768 Square Butte Creek below Center, ND −101.1957 Burnt Creek Tributary near Baldwin, ND −100.7921 Burnt Creek Tributary No. 2 near Baldwin, ND −100.7907 Burnt Creek near Bismarck, ND −100.8137 Missouri River at Bismarck, ND −100.8214 186,400 Heart River near South Heart, ND −102.9485 Heart River Tributary near South Heart, ND −102.9199 Heart River below Dickinson Dam near Dickinson, ND −102.8166
Appendix C1 153 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Heart River Tributary near Dickinson, ND −102.7899 Heart River at Dickinson, ND −102.7352 Heart River at Lehigh, ND −102.7102 Green River near New Hradec, ND −103.0532 Green River near Gladstone, ND −102.6241 Antelope Creek near Dickinson, ND −102.7907 Antelope Creek Tributary near New England, ND −102.7907 Antelope Creek Tributary Site No. 2 near New England, ND −102.7907 Heart River near Richardton, ND −102.3083 1,240 Government Creek near Richardton, ND −102.3102 Heart River above Lake Tschida near Glen Ullin, ND −102.0793 1,530 Heart River below Heart Butte Dam near Glen Ullin, ND −101.8018 1,710 Antelope Creek near Carson, ND −101.6454 Tavis Creek near Glen Ullin, ND −101.8577
154 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Big Muddy Creek near Almont, ND −101.4674 Heart River near Lark, ND −101.3821 2,750 Heart River at Stark Bridge near Judson, ND −101.2136 2,930 Sweetbriar Creek near Judson, ND −101.2532 Heart River near Mandan, ND −100.9746 3,310 3,310 Southeast Branch Little Heart River at St. An thony, ND −100.9037 Dead Buffalo Lake Tributary near Steele, ND −99.8265 West Branch Long Lake Creek near Hazelton, ND −100.1559 Long Lake Creek above Long Lake near Moffit, ND −100.2418 Apple Creek near Menoken, ND −100.6573 1,680 1,180 Hay Creek at 43rd Avenue near Bismarck, ND −100.7587 Hay Creek at Divide Avenue in Bismarck, ND −100.7373 Hay Creek at Main Avenue in Bismarck, ND −100.7340 Cannonball River at Regent, ND −102.5518
Appendix C1 155 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Cannonball River below Bentley, ND −102.0421 1,140 Cannonball River near Raleigh, ND −101.3332 1,640 Middle Fork Cedar Creek Tributary near Amidon, ND −103.2935 White Butte Fork Cedar Creek near Scranton, ND −102.9963 Cedar Creek near Haynes, ND −102.4757 Timber Creek Tributary near New Leipzig, ND −101.9576 Cedar Creek near Pretty Rock, ND −101.8324 1,340 Cedar Creek near Raleigh, ND −101.3337 1,750 Cannonball River near Timmer, ND −101.0043 3,650 Louise Creek Tributary near Brisbane, ND −101.4893 Louise Creek Tributary near Lark, ND −101.4171 Louise Creek Tributary No. 2 near Lark, ND −101.3324 Louise Creek above Flasher, ND −101.2490 Cannonball River at Breien, ND −100.9344 4,100 4,100
156 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Beaver Creek Tributary near Linton, ND −100.0801 Beaver Creek at Linton, ND −100.2332 Beaver Creek below Linton, ND −100.2526 Spring Creek near Linton, ND −100.2309 Sand Creek Tributary near Hazelton, ND −100.2976 Sand Creek near Temvik, ND −100.3448 Spring Creek near Herreid, SD −100.1082 2,027 Oak Creek near Wakpala, SD −100.5593 Spring Creek near Bowman, ND −103.4102 Spring Creek Tributary near Bowman, ND −103.4102 North Fork Grand River at Haley, ND −103.1196 Buffalo Creek Tributary near Buffalo Springs, ND −103.2768 Buffalo Creek Tributary near Gascoyne, ND −103.0393 North Fork Grand River Tributary near Lodgepole, SD −102.6515 North Fork Grand River near White Butte, SD −102.3624 1,202 1,202
Appendix C1 157 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year South Fork Grand River at Buffalo, SD −103.5444 Wide Sandy Creek near Buffalo, SD −103.5457 North Jack Creek near Ludlow, SD −103.3957 South Fork Grand River near Cash, SD −102.6433 1,305 1,305 South Fork Grand River Tributary near Bison, SD −102.6582 Grand River at Shadehill, SD −102.1960 2,996 2,996 Willow Creek near Keldron, SD −101.8678 Grand River at Little Eagle, SD −100.8182 5,316 5,316 Grand River near Wakpala, SD −100.6393 5,423 5,423 Claymore Creek near Mobridge, SD −100.5543 Claymore Creek Tributary near Trail City, SD −100.5826 Claymore Creek Tributary No. 2 near Trail City, SD −100.5926 Missouri River near Mobridge, SD −100.4737 208,700 208,700 Deadman Creek Tributary near Mobridge, SD −100.4988 Blue Blanket Creek Tribu tary near Glenham, SD −100.2007
158 Potential Effects of Energy Development, Williston Basin—Water Resources Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Battle Creek Tributary near Castle Rock, SD −103.5494 South Fork Moreau River Tributary near Redig, SD −103.5696 Sand Creek Tributary near Redig, SD −103.5494 North Fork Moreau River Tributary near Redig, SD −103.5496 Moreau River at Bixby, SD −102.5588 1,570 1,570 Deep Creek Tributary near Maurine, SD −102.5418 Moreau River near Faith, SD −102.1565 2,596 2,596 Thunder Butte Creek Tribu tary near Meadow, SD −102.0896 Thunder Butte Creek Tribu tary near Glad Valley, SD −102.0164 Elm Creek Tributary near Dupree, SD −101.6446 Moreau River near Eagle Butte, SD −101.2185 4,320 4,320 Little Moreau River Tribu tary near Firesteel, SD −101.2254 Moreau River near Whitehorse, SD −100.8429 4,889 4,872 Moreau River at Promise, SD −100.6029 5,223 5,223 Elk Creek near Elm Springs, SD −102.5032 Horse Creek above Vale, SD −103.3667
Appendix C1 159 Table 1-1. Summary information on U.S. Geological Survey streamgages in the study area that have 10 or more years of data collection through water year 2014.—Continued [ND, North Dakota; No., Number; MT, Montana; SD, South Dakota] Map number (fig. 1-1) Streamgage number Streamgage name Latitude, in decimal degrees Longitude, in decimal degrees Total drainage area, in square miles Contributing drainage area, in square miles Start of annual peak-flow data collection, water year End of annual peak-flow data collection, water year Number of years of annual peak-flow data collection Start of year-round or seasonal continuous streamflow data collection, water year End of year-round or seasonal continuous streamflow data collection through water year 2014, water year Horse Creek near Vale, SD −103.3385 Belle Fourche River near Sturgis, SD −103.1368 5,821 5,814 Elm Creek near Fairpoint, SD −103.0624 Belle Fourche River near Elm Springs, SD −102.5665 7,029 7,022 Cheyenne River near Plainview, SD −101.9302 21,425 21,414 Elm Creek near Red Owl, SD −102.4491 Cherry Creek near Plain view, SD −102.0535 1,190 1,190 Cherry Creek Tributary near Avance, SD −102.0554 Cherry Creek Tributary No. 2 near Avance, SD −102.0554 Cherry Creek Tributary No. 3 near Avance, SD −102.0438 Beaver Creek near Faith, SD −102.0440 Cheyenne River at Cherry Creek, SD −101.4979 23,643 23,632 Cottonwood Creek near Cherry Creek, SD −101.4049 Cheyenne River near Eagle Butte, SD −101.2174 24,311 24,300
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Bartos and others—Potential Effects of Energy Development, Williston Basin—Water Resources—SIR 2017-5070-C, ver. 1.1 ISSN 2328-0328 (online) ://doi.org/10.3133/sir20175070C