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^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ^ _ ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! . . . . . . . . . . . . . . ^ _ ^ _ ^ _ ^ _ ^ _ ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! Pablo Ronan Dixon Arlee Marion Somers Polson Charlo Bigfork Whitefish Kalispell Swan Lake Hot Springs St Ignatius West Glacier Columbia Falls Legend Lakes Streams Cities or towns Study area County boundaries Legend Generalized geology Statewide ground-water monitoring network wells Wells visited during the Flathead Lake Ground-Water Characterization Study Alluvium along major drainages Glacial deposits Tertiary basin fill Map F. Geographic and cultural features Map G. Generalized geology, statewide monitoring wells, and wells visited during the Flathead Lake Ground-Water Characterization Study Legend Map B. Well density per section in 1980 0 1 - 10 11 - 30 31 - 50 51 - 80 Number of well records per section: NO OU TLINE Map A. Well density per section in 1970 Legend Number of well records per section: NO OU TLINE 0 31 - 50 51 - 80 Legend Number of well records per section: Legend Number of well records per section: Legend Number of well records per section: NO OU TLINE 0 1 - 10 11 - 30 31 - 50 51 - 80 81 - 160 NO OU TLINE 0 1 - 10 11 - 30 31 - 50 51 - 80 81 - 160 NO OU TLINE 0 1 - 10 11 - 30 31 - 50 51 - 80 81 - 160 51 - 80 81 - 160 Legend Number of well records per section: Map C. Well density per section in 1990 Map D. Well density per section in 2000 Map E. Well density per section in 2005 Map H. Distribution of alluvium, sections with over 50 wells (2005), and selected hydrographs FLATHEA D LAKE HUNGRY HORSE RES. North Fork Flathead R. Middle Fork Flathead R. South Fork Flathead R. Flathead R. Stillwater R. Whitefish R. Swan R. Flathead R. Flathead R. Jocko R. Little Bitterroot R. LAKE MCDONALD WHITEFISH LAKE ASHLEY LAKE LITTLE BITTERROOT LAKE SWA N LAKE Montana Bureau of Mines and Geology A Department of Montana Tech of The University of Montana Ground-Water Open-File Report 19, Sheet 1 November, 2007 Sheet 1. The number of water wells per section in 1970, 1980, 1990, 2000, and 2005. 0 10 20 5 Miles . . 0 10 20 5 Miles . 0 10 20 5 Miles . 0 10 20 5 Miles . 0 10 20 5 Miles . 0 10 20 5 Miles . 0 10 20 5 Miles . 0 10 20 5 Miles The study area is defined by the Flathead Lake Ground-Water Characterization Area (LaFave and others, 2004). Maps A through E illustrate the number of water-well records per Public Land Survey System (PLSS) section in 10-year increments beginning in 1970 and include water-well records present in the GWIC database at the beginning of each stated year. Figure 1 (below) shows the progression graphically through 2005. While the number of PLSS sections with at least one well is increasing, the total number of wells is increasing at a much greater rate (note the separate scales in Figure 1). Throughout the map series, some PLSS sections that have small numbers of wells in non-valley locations result from in- correctly located wells in GWIC. Map F shows selected lakes, streams, cities, towns, and counties within the study area. Map G illustrates the general geology within the intermontane basins, locations of wells visited during the Flathead Lake Ground-Water Characterization Study, and the locations of statewide ground-water moni- toring wells. Comparison of the locations of visited and statewide monitoring network wells with the PLSS section well densities shown on maps D and E shows that data from the visited wells and water-level records from the monitoring network are relevant to the most developed aquifers. These aquifers typically include large thicknesses of valley-fill aquifer materials. The alluvium shown on Map G includes largely surficial, generally unconsolidated sediments that are in relatively good hydrologic connection with surface water. Map H shows PLSS sections that contained more than 50 wells in 2005, the alluvial aquifers, and hydro- graphs from selected statewide monitoring wells. The hydrographs show ground-water storage or pressure change in some of the most used aquifers. References LaFave, J.I., Smith, L.N., and Patton, T.W., 2004, Ground- water resources of the Flathead Lake Area: Flathead, Lake, and parts of Missoula and Sanders Counties: Part A- Descriptive overview: Montana Bureau of Mines and Geology Ground-Water Assessment Atlas 2A, 132 p. Natural Resource Information System, Montana State Library, for base map coverages (http://nris.mt.gov/). Explanation Introduction Acknowledgments This report is primarily funded by a Montana Department of Natural Resources and Conservation grant obtained by the Clark Fork Basin Task Force, a voluntary citizen's group functioning as a consensus-based, collaborative watershed advisory committee. These maps are based on data from the Montana Ground-Water Information Center (GWIC) database (http://mbmggwic.mtech.edu/), and display how ground water has been developed in the Flathead Lake Ground-Water Characterization Area. F L A T H E A D L A K E Alluvium S A N D E R S MISSOULA Major highways Township boundaries Scale 1:792,000 Scale 1:792,000 Scale 1:792,000 ^ _ T37N T33N T29N T24N T20N T15N R25W R21W R18W T35N T29N T24N T20N R16W R21W R24W ! 952 sections with at least one well Total number of wells in study area: 3,421 1,295 sections with at least one well Total number of wells in study area: 6,894 1,486 sections with at least one well Total number of wells in study area: 10,296 SCALE 1:1,000,000 SCALE 1:1,000,000 SCALE 1:1,000,000 SCALE 1:1,000,000 1 - 10 11 - 30 By Kirk B. Waren and Thomas W. Patton Ground-Water Resource Development in the Flathead Lake Ground- Water Characterization Area, Flathead, Lake, Missoula, and Sanders Counties, Montana 1,842 sections with at least one well Total number of wells in study area: 18,327 SCALE 1:1,000,000 s Cities or towns (see Map F) Bedrock As of 2005, 47 sections within the Flathead Lake Ground- Water Characterization Area had more than 50 wells. Of those, 43 sections intersected the alluvium. Eight of these sections are completely within the alluvium. Long-term water-level records from selected monitoring wells are shown in the inset graphs. Well 85689 T30N, R20W, Section 22, CDAC, Total Depth 308 ft. 3000 3010 3020 3030 3040 1/1/1992 1/1/1996 1/1/2000 1/1/2004 1/1/2008 DATE GROUND-WATER ELEVATION (FT) Well 85628 T30N, R20W, Section 20, DCCA, Total Depth 149 ft. 2940 2950 2960 2970 2980 2990 1/1/1992 1/1/1996 1/1/2000 1/1/2004 1/1/2008 DATE GROUND-WATER ELEVATION (FT) Well 148189 T30N, R20W, Section 19, DAAC, Total Depth 342 ft. 2950 2960 2970 2980 1/1/1992 1/1/1996 1/1/2000 1/1/2004 1/1/2008 DATE GROUND-WATER ELEVATION (FT) Well 6419 T28N, R21W, Section 4, DCDA Total Depth 23 ft. 2890 2900 2910 2920 1/1/1984 1/1/1988 1/1/1992 1/1/1996 1/1/2000 1/1/2004 1/1/2008 DATE GROUND-WATER ELEVATION (FT) Montana Ground-Water Information Center, Montana Bureau of Mines and Geology, Montana Tech of The University of Montana (http://mbmggwic.mtech.edu/). 1,710 sections with at least one well Total number of wells in study area: 15,050 R11W R16W 5 Cities or towns (see Map F) Figure 1. GWIC database records for wells within the Flathead Lake Ground-Water Characterization Area 0 5,000 10,000 15,000 20,000 1960 1970 1980 1990 2000 2010 0 500 1,000 1,500 2,000 2,500 Total number of well records Number of sections with at least one well Well 131524 T29N, R21W, Section 20, CCCC, Total Depth 278 ft. 2880 2890 2900 2910 2920 2930 1/1/1962 1/1/1970 1/1/1978 1/1/1986 1/1/1994 1/1/2002 DATE GROUND-WATER ELEVATION (FT)
