June 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 Reservoir1.3
1Marias Above Tiber Reservoir1.3
2Tobacco-0.9
2Tobacco-0.9
3Kootenai to Libby Dam-1.7
3Kootenai to Libby Dam-1.7
4Kootenai River below Libby Dam-0.3
4Kootenai River below Libby Dam-0.3
5Fisher River-2.4
5Fisher River-2.4
6Yaak River-1.9
6Yaak River-1.9
7North FK. Flathead River-0.8
7North FK. Flathead River-0.8
8Middle FK. Flathead River0.4
8Middle FK. Flathead River0.4
9South FK. Flathead River-0.2
9South FK. Flathead River-0.2
10Flathead at Columbia Falls-0.2
10Flathead at Columbia Falls-0.2
11Stillwater/Whitefish Rivers-1.1
11Stillwater/Whitefish Rivers-1.1
12Swan River-1.7
12Swan River-1.7
13Flathead River at Polson-0.5
13Flathead River at Polson-0.5
14Mission Valley-1.8
14Mission Valley-1.8
15Little Bitterroot River-2.8
15Little Bitterroot River-2.8
16Clark above Missoula0.8
16Clark above Missoula0.8
17Blackfoot River-1.3
17Blackfoot River-1.3
18Clark Fork above Missoula-0.4
18Clark Fork above Missoula-0.4
19Bitterroot River-1.3
19Bitterroot River-1.3
20Clark Fork River below Bitterroot River-0.6
20Clark Fork River below Bitterroot River-0.6
21Clark Fork River below Flathead River-0.5
21Clark Fork River below Flathead River-0.5
22Beaverhead River3.4
22Beaverhead River3.4
23Ruby River3.5
23Ruby River3.5
24Big Hole River3
24Big Hole River3
25Boulder River (Jefferson)1.6
25Boulder River (Jefferson)1.6
26Jefferson River3
26Jefferson River3
27Madison River3.4
27Madison River3.4
28Gallatin River2.4
28Gallatin River2.4
29Missouri River above Canyon Ferry3
29Missouri River above Canyon Ferry3
30Missouri River below Canyon Ferry2.4
30Missouri River below Canyon Ferry2.4
31Smith River0
31Smith River0
32Sun River2
32Sun River2
33Teton River0.2
33Teton River0.2
34Birch/Dupuyer0.9
34Birch/Dupuyer0.9
36Musselshell River1.9
36Musselshell River1.9
37Missouri River above Fort Peck1.5
37Missouri River above Fort Peck1.5
38Missouri River below Fort Peck0.6
38Missouri River below Fort Peck0.6
39Milk River-0.8
39Milk River-0.8
41Yellowstone River above Livingston0.5
41Yellowstone River above Livingston0.5
42Shields River1.2
42Shields River1.2
43Boulder River (Yellowstone)0
43Boulder River (Yellowstone)0
44Stillwater River0.7
44Stillwater River0.7
45Rock/Red Lodge Creeks1.8
45Rock/Red Lodge Creeks1.8
46Clarks Fork River0.9
46Clarks Fork River0.9
47Yellowstone River above Bighorn River0.4
47Yellowstone River above Bighorn River0.4
48Bighorn River below Bighorn Lake1.3
48Bighorn River below Bighorn Lake1.3
49Little Bighorn River2.1
49Little Bighorn River2.1
50Yellowstone River below Bighorn River0.9
50Yellowstone River below Bighorn River0.9
51Tongue River2.5
51Tongue River2.5
52Powder River1.8
52Powder River1.8
999Kootenai at Ft. Steele-0.5
999Kootenai at Ft. Steele-0.5