July 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 Reservoir2.7
1Marias Above Tiber Reservoir2.7
2Tobacco1.7
2Tobacco1.7
3Kootenai to Libby Dam1.7
3Kootenai to Libby Dam1.7
4Kootenai River below Libby Dam1.3
4Kootenai River below Libby Dam1.3
5Fisher River0.4
5Fisher River0.4
6Yaak River0
6Yaak River0
7North FK. Flathead River1.6
7North FK. Flathead River1.6
8Middle FK. Flathead River0.7
8Middle FK. Flathead River0.7
9South FK. Flathead River0
9South FK. Flathead River0
10Flathead at Columbia Falls1
10Flathead at Columbia Falls1
11Stillwater/Whitefish Rivers1
11Stillwater/Whitefish Rivers1
12Swan River-1.2
12Swan River-1.2
13Flathead River at Polson-0.8
13Flathead River at Polson-0.8
14Mission Valley-0.5
14Mission Valley-0.5
15Little Bitterroot River-2.9
15Little Bitterroot River-2.9
16Clark above Missoula1
16Clark above Missoula1
17Blackfoot River-0.4
17Blackfoot River-0.4
18Clark Fork above Missoula0.8
18Clark Fork above Missoula0.8
19Bitterroot River-0.2
19Bitterroot River-0.2
20Clark Fork River below Bitterroot River0.5
20Clark Fork River below Bitterroot River0.5
21Clark Fork River below Flathead River-0.4
21Clark Fork River below Flathead River-0.4
22Beaverhead River3.3
22Beaverhead River3.3
23Ruby River3
23Ruby River3
24Big Hole River2.8
24Big Hole River2.8
25Boulder River (Jefferson)1.8
25Boulder River (Jefferson)1.8
26Jefferson River3
26Jefferson River3
27Madison River3
27Madison River3
28Gallatin River0.9
28Gallatin River0.9
29Missouri River above Canyon Ferry2.6
29Missouri River above Canyon Ferry2.6
30Missouri River below Canyon Ferry2.2
30Missouri River below Canyon Ferry2.2
31Smith River1.5
31Smith River1.5
32Sun River2.1
32Sun River2.1
33Teton River1.9
33Teton River1.9
34Birch/Dupuyer2.5
34Birch/Dupuyer2.5
36Musselshell River2.6
36Musselshell River2.6
37Missouri River above Fort Peck2.9
37Missouri River above Fort Peck2.9
38Missouri River below Fort Peck1.4
38Missouri River below Fort Peck1.4
39Milk River1.6
39Milk River1.6
41Yellowstone River above Livingston-0.5
41Yellowstone River above Livingston-0.5
42Shields River0.6
42Shields River0.6
43Boulder River (Yellowstone)0
43Boulder River (Yellowstone)0
44Stillwater River-0.2
44Stillwater River-0.2
45Rock/Red Lodge Creeks1.8
45Rock/Red Lodge Creeks1.8
46Clarks Fork River-0.9
46Clarks Fork River-0.9
47Yellowstone River above Bighorn River-0.5
47Yellowstone River above Bighorn River-0.5
48Bighorn River below Bighorn Lake0.9
48Bighorn River below Bighorn Lake0.9
49Little Bighorn River1.5
49Little Bighorn River1.5
50Yellowstone River below Bighorn River0.4
50Yellowstone River below Bighorn River0.4
51Tongue River2.1
51Tongue River2.1
52Powder River2.5
52Powder River2.5
999Kootenai at Ft. Steele1.6
999Kootenai at Ft. Steele1.6