City of Cut Bank Public Water Supply PWSID # MT0000193 Date of Report: March 20, 2003 SOURCE WATER DELINEATION AND ASSESSMENT REPORT Operator/Manager: Keith Nelson 113 East Main Street Cut Bank, MT 59427 (406) 873-2362 City of Cut Bank SWDAR Table of Contents INTRODUCTION .....................................................................................................................................................................1 PURPOSE...............................................................................................................................................................................1 LIMITATIONS.......................................................................................................................................................................1 BACKGROUND........................................................................................................................................................................2 THE COMMUNITY...............................................................................................................................................................2 CLIMATE...............................................................................................................................................................................2 GEOGRAPHIC SETTING .....................................................................................................................................................3 GEOLOGY .............................................................................................................................................................................3 THE PUBLIC WATER SUPPLY...........................................................................................................................................4 CUT BANK PWS WATER QUALITY .................................................................................................................................5 DELINEATION.........................................................................................................................................................................6 HYDROGEOLOGIC CONDITIONS.....................................................................................................................................6 CONCEPTUAL MODEL AND ASSUMPTIONS.................................................................................................................7 DELINEATION RESULTS ...................................................................................................................................................8 Spill Response Region ........................................................................................................................................................8 Watershed Region ..............................................................................................................................................................8 LIMITING FACTORS ...........................................................................................................................................................8 INVENTORY.............................................................................................................................................................................9 INVENTORY METHOD .......................................................................................................................................................9 INVENTORY RESULTS/SPILL RESPONSE REGION ....................................................................................................10 INVENTORY RESULTS/WATERSHED REGION ...........................................................................................................12 INVENTORY UPDATE.......................................................................................................................................................15 INVENTORY LIMITATIONS.............................................................................................................................................15 SUSCEPTIBILITY ASSESSMENT.......................................................................................................................................16 SUSCEPTIBILITY ASSESSMENT RESULTS ..................................................................................................................18 MANAGEMENT RECOMMENDATIONS ........................................................................................................................23 MONITORING WAIVERS....................................................................................................................................................26 WAIVER RECOMMENDATION .......................................................................................................................................26 MONITORING WAIVER REQUIREMENTS ....................................................................................................................27 Use Waivers .....................................................................................................................................................................27 Susceptibility Waivers ......................................................................................................................................................27 Susceptibility Waiver for Confined Aquifers ....................................................................................................................28 Susceptibility Waiver for Unconfined Aquifers ................................................................................................................28 REFERENCES ........................................................................................................................................................................30 GLOSSARY* ...........................................................................................................................................................................31 FIGURES .................................................................................................................................................................................33 FIGURE 1: GENERAL LOCATION MAP..........................................................................................................................34 FIGURE 2: CLIMATE SUMMARY GRAPH – IMBEDDED IN TEXT ON PAGE 3. .....................................................35 FIGURE 3: SPILL RESPONSE REGION MAP WITH OTHER PUBLIC WATER SUPPLIES IN THE AREA..............36 FIGURE 4: GENERAL GEOLOGIC MAP..........................................................................................................................37 FIGURE 5: DAILY FLOW FOR CUT BANK CREEK AT CUT BANK – IMBEDDED IN TEXT ON PAGE 6............38 FIGURE 6: PEAK FLOW LEVELS FOR THE CUT BANK CREEK AT CUT BANK – IMBEDDED IN TEXT ON PAGE 6.................................................................................................................................................................................39 i City of Cut Bank SWDAR FIGURE 7: SPILL RESPONSE REGION AND LANDCOVER / LANDUSE MAP .........................................................40 FIGURE 8: WATERSHED REGION INVENTORY MAP.................................................................................................41 FIGURE 9: CUT BANK PWS WATERSHED REGION LANDCOVER / LANDUSE MAP. ..........................................42 APPENDICES..........................................................................................................................................................................43 APPENDIX A - LISTING OF POTENTIAL CONTAMINANT SOURCES BY SIC CODE AND SUPPLEMENTAL LIST PROVIDED BY PWS OPERATOR ...........................................................................................................................44 APPENDIX B - DEQ PWS’S DATABASE OUTPUT ........................................................................................................47 APPENDIX C - SANITARY SURVEY...............................................................................................................................54 APPENDIX D - CONCURRENCE LETTER & OTHER CORRESPONDENCE ..............................................................55 ii City of Cut Bank SWDAR INTRODUCTION This Delineation and Assessment Report was prepared by Jim Stimson, a hydrogeologist with the Source Water Protection Program of the Montana Department of Environmental Quality (DEQ). Cut Bank public water supply (PWS) is located in Glacier County, Montana, about 110 miles north and west of Great Falls and about 30 miles west of Shelby (Figure 1). The DEQ PWS identification number, operator name, and operator number for the Cut Bank PWS appear on the title page of this report. Purpose This report is intended to meet the technical requirements for the completion of the source water delineation and assessment report for the Cut Bank PWS as required by the Montana Source Water Protection Program (DEQ, 1999) and the federal Safe Drinking Water Act (SDWA) Amendments of 1996 (P.L. 104-182). The Montana Source Water Protection Program is intended to be a practical and cost- effective approach to the protection of public drinking water supplies from contamination. The primary purpose of this source water delineation and assessment report is to provide information to