August 1996
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 Reservoir2.6
1Marias Above Tiber Reservoir2.6
2Tobacco1.8
2Tobacco1.8
3Kootenai to Libby Dam1.7
3Kootenai to Libby Dam1.7
4Kootenai River below Libby Dam1.4
4Kootenai River below Libby Dam1.4
5Fisher River1.3
5Fisher River1.3
6Yaak River1.3
6Yaak River1.3
7North FK. Flathead River1.4
7North FK. Flathead River1.4
8Middle FK. Flathead River1.3
8Middle FK. Flathead River1.3
9South FK. Flathead River0.9
9South FK. Flathead River0.9
10Flathead at Columbia Falls1.2
10Flathead at Columbia Falls1.2
11Stillwater/Whitefish Rivers1.6
11Stillwater/Whitefish Rivers1.6
12Swan River1
12Swan River1
13Flathead River at Polson1.2
13Flathead River at Polson1.2
14Mission Valley0.1
14Mission Valley0.1
15Little Bitterroot River2.9
15Little Bitterroot River2.9
16Clark above Missoula0.6
16Clark above Missoula0.6
17Blackfoot River1.2
17Blackfoot River1.2
18Clark Fork above Missoula0.9
18Clark Fork above Missoula0.9
19Bitterroot River1.8
19Bitterroot River1.8
20Clark Fork River below Bitterroot River1.1
20Clark Fork River below Bitterroot River1.1
21Clark Fork River below Flathead River1.2
21Clark Fork River below Flathead River1.2
22Beaverhead River-0.6
22Beaverhead River-0.6
23Ruby River-0.5
23Ruby River-0.5
24Big Hole River0.1
24Big Hole River0.1
25Boulder River (Jefferson)-1.5
25Boulder River (Jefferson)-1.5
26Jefferson River-0.5
26Jefferson River-0.5
27Madison River-0.1
27Madison River-0.1
28Gallatin River-1.2
28Gallatin River-1.2
29Missouri River above Canyon Ferry-0.4
29Missouri River above Canyon Ferry-0.4
30Missouri River below Canyon Ferry0.2
30Missouri River below Canyon Ferry0.2
31Smith River-1.1
31Smith River-1.1
32Sun River2.2
32Sun River2.2
33Teton River0.8
33Teton River0.8
34Birch/Dupuyer3
34Birch/Dupuyer3
36Musselshell River1
36Musselshell River1
37Missouri River above Fort Peck2.2
37Missouri River above Fort Peck2.2
38Missouri River below Fort Peck1.6
38Missouri River below Fort Peck1.6
39Milk River0.7
39Milk River0.7
41Yellowstone River above Livingston0.6
41Yellowstone River above Livingston0.6
42Shields River-1.6
42Shields River-1.6
43Boulder River (Yellowstone)1.1
43Boulder River (Yellowstone)1.1
44Stillwater River1.1
44Stillwater River1.1
45Rock/Red Lodge Creeks1.5
45Rock/Red Lodge Creeks1.5
46Clarks Fork River0.7
46Clarks Fork River0.7
47Yellowstone River above Bighorn River0.8
47Yellowstone River above Bighorn River0.8
48Bighorn River below Bighorn Lake1.2
48Bighorn River below Bighorn Lake1.2
49Little Bighorn River-1.7
49Little Bighorn River-1.7
50Yellowstone River below Bighorn River1
50Yellowstone River below Bighorn River1
51Tongue River-1.5
51Tongue River-1.5
52Powder River-1.9
52Powder River-1.9
999Kootenai at Ft. Steele1
999Kootenai at Ft. Steele1