February 1995
Surface Water Supply Index Report

Provided by the US Natural Resources Conservation Service
Bozeman, Montana

The SWSI is designed for areas that rely primarily on snowmelt runoff as the primary source of surface water. The SWSI accounts for snowpack, mountain precipitation, streamflow, reservoir contents, and soil moisture conditions. The SWSI can be used by irrigators, fisheries personnel, recreationists, and others who utilize surface waters. SWSI values are categorized as follows:

IDBasin NameValue
1Marias Above Tiber Reservoir-0.2
1Marias Above Tiber Reservoir-0.2
2Tobacco0.5
2Tobacco0.5
3Kootenai to Libby Dam0.4
3Kootenai to Libby Dam0.4
4Kootenai River below Libby Dam0.6
4Kootenai River below Libby Dam0.6
5Fisher River0
5Fisher River0
6Yaak River-0.4
6Yaak River-0.4
7North FK. Flathead River0
7North FK. Flathead River0
8Middle FK. Flathead River0
8Middle FK. Flathead River0
9South FK. Flathead River-0.6
9South FK. Flathead River-0.6
10Flathead at Columbia Falls-0.2
10Flathead at Columbia Falls-0.2
11Stillwater/Whitefish Rivers0.3
11Stillwater/Whitefish Rivers0.3
12Swan River-0.2
12Swan River-0.2
13Flathead River at Polson-0.3
13Flathead River at Polson-0.3
14Mission Valley-0.7
14Mission Valley-0.7
15Little Bitterroot River-0.9
15Little Bitterroot River-0.9
16Clark above Missoula-1.1
16Clark above Missoula-1.1
17Blackfoot River-1.4
17Blackfoot River-1.4
18Clark Fork above Missoula-1.3
18Clark Fork above Missoula-1.3
19Bitterroot River-1
19Bitterroot River-1
20Clark Fork River below Bitterroot River-1.2
20Clark Fork River below Bitterroot River-1.2
21Clark Fork River below Flathead River-0.6
21Clark Fork River below Flathead River-0.6
22Beaverhead River-0.6
22Beaverhead River-0.6
23Ruby River1.8
23Ruby River1.8
24Big Hole River0.6
24Big Hole River0.6
25Boulder River (Jefferson)0.5
25Boulder River (Jefferson)0.5
26Jefferson River0.5
26Jefferson River0.5
27Madison River3.1
27Madison River3.1
28Gallatin River1.3
28Gallatin River1.3
29Missouri River above Canyon Ferry1.6
29Missouri River above Canyon Ferry1.6
30Missouri River below Canyon Ferry1.1
30Missouri River below Canyon Ferry1.1
31Smith River-1
31Smith River-1
32Sun River-2.3
32Sun River-2.3
33Teton River-2.2
33Teton River-2.2
34Birch/Dupuyer-1.6
34Birch/Dupuyer-1.6
36Musselshell River-0.5
36Musselshell River-0.5
37Missouri River above Fort Peck0.6
37Missouri River above Fort Peck0.6
38Missouri River below Fort Peck0.1
38Missouri River below Fort Peck0.1
39Milk River-1.9
39Milk River-1.9
41Yellowstone River above Livingston0.4
41Yellowstone River above Livingston0.4
42Shields River0.6
42Shields River0.6
43Boulder River (Yellowstone)0.5
43Boulder River (Yellowstone)0.5
44Stillwater River0.4
44Stillwater River0.4
45Rock/Red Lodge Creeks0.2
45Rock/Red Lodge Creeks0.2
46Clarks Fork River0.2
46Clarks Fork River0.2
47Yellowstone River above Bighorn River0.3
47Yellowstone River above Bighorn River0.3
48Bighorn River below Bighorn Lake-0.4
48Bighorn River below Bighorn Lake-0.4
49Little Bighorn River-1.4
49Little Bighorn River-1.4
50Yellowstone River below Bighorn River0.5
50Yellowstone River below Bighorn River0.5
51Tongue River-0.4
51Tongue River-0.4
52Powder River1.9
52Powder River1.9
999Kootenai at Ft. Steele-0.8
999Kootenai at Ft. Steele-0.8