GROUNDWATER RESOURCES OF THE LIVINGSTON AND LOWER SHIELDS RIVER VALLEY AREAS, PARK COUNTY, MONTANA Montana Bureau of Mines and Geology Open-File Report 680 John Olson, Shawn Kuzara, and Elizabeth Meredith 2016 CONTENTS Abstract ........................................................................................................................................................ 1 Introduction .................................................................................................................................................. 3 Purpose .................................................................................................................................................. 3 Location .................................................................................................................................................. 3 Methods ...................................................................................................................................................... 3 Watershed issues.......................................................................................................................................... 6 Land and Water Use ............................................................................................................................... 6 Population Growth and Rural Residential Development ........................................................................6 Energy Development .................................................................................................................................... 9 Hydrologic influences ................................................................................................................................... 10 Topography ............................................................................................................................................. 10 Climate ................................................................................................................................................... 10 Drainage ................................................................................................................................................. 10 Geologic Setting............................................................................................................................................ 14 Hydrogeologic Units ..................................................................................................................................... 14 Quaternary Unconsolidated Aquifers ..................................................................................................... 14 Gravel underlying pediment surfaces ..................................................................................................... 16 Bedrock Aquifers above the Colorado Group ......................................................................................... 16 Colorado Group ..................................................................................................................................... 16 Ellis Group .............................................................................................................................................. 17 Groundwater Flow ........................................................................................................................................ 18 Aquifer Flow Properties .......................................................................................................................... 18 Groundwater Flow in Bedrock Units ...................................................................................................... 20 Groundwater Flow in the Alluvial Aquifers ............................................................................................. 20 iii Groundwater Quality .................................................................................................................................... 20 Common Ion Water Geochemistry ......................................................................................................... 20 Nitrate Concentrations ........................................................................................................................... 20 Groundwater Recharge ................................................................................................................................ 21 Quantification of Recharge to Alluvial Aquifers ...................................................................................... 22 Groundwater Level Fluctuation Method .......................................................................................... 22 Groundwater Flux Method ............................................................................................................... 24 Quantification of Recharge to Bedrock Aquifers .................................................................................... 25 Stream Baseflow Method ................................................................................................................. 25 Chloride Tracer Method.................................................................................................................... 26 Identifying Sources and Age of Recharge ............................................................................................... 28 Stable Isotopes ................................................................................................................................. 28 Tritium .............................................................................................................................................. 29 Sodium percentages ......................................................................................................................... 31 Aquifer Vulnerability ............................................................................................................................... 32 Summary ..................................................................................................................................................... 35 Recommendations........................................................................................................................................ 35 References .................................................................................................................................................... 36 Appendix A. Well Inventory .......................................................................................................................... 39 Appendix B. Stream Inventory ...................................................................................................................... 45 Appendix C. Water Quality ........................................................................................................................... 49 Appendix D. Nitrate Concentrations ............................................................................................................. 55 Appendix E. Isotope Results ......................................................................................................................... 61 Appendix F. Aquifer Tests ............................................................................................................................. 65 iv FIGURES Figure 1. The project location includes the Shields River watershed and smaller watersheds around Livingston ............................................................................................................................................... 2 Figure 2. Locations of watersheds in the project area. .......................................................................................4 Figure 3. Groundwater field inventory and water-quality sample locations ......................................................5 Figure 4. Land cover in the project area .............................................................................................................7 Figure 5. The distribution of wells drilled between 1994 and 2004 in the project area.....................................8 Figure 6. Potential coalbed-methane development (by depth) in the Eagle sandstone west of Livingston. ......9 Figure 7. Ground-surface elevation in the project area. ...................................................................................11 Figure 8. The distribution of average annual precipitation from rain and snow ..............................................12 Figure 9. Mountain precipitation and average annual Shields River flow rate indicate the area experienced a drought beginning in 1998.................................................................................................................13 Figure 10. Location of the groundwater contamination plume from the Burlington Northern Shop Complex in Livingston .......................................................................................................................................... 15 Figure 11. Piper plot showing water chemistry in the Yellowstone River alluvial aquifer and Yellowstone irrigation water ..................................................................................................................................... 21 Figure 12. Piper plot showing bedrock groundwater chemistry. ......................................................................22 Figure 13. Recharge calculation by water level fluctuation in well 12953. ......................................................23