August 1993
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 Reservoir1.8
1Marias Above Tiber Reservoir1.8
2Tobacco0.9
2Tobacco0.9
3Kootenai to Libby Dam0.2
3Kootenai to Libby Dam0.2
4Kootenai River below Libby Dam-0.3
4Kootenai River below Libby Dam-0.3
5Fisher River1.2
5Fisher River1.2
6Yaak River0.5
6Yaak River0.5
7North FK. Flathead River1.4
7North FK. Flathead River1.4
8Middle FK. Flathead River0.5
8Middle FK. Flathead River0.5
9South FK. Flathead River0
9South FK. Flathead River0
10Flathead at Columbia Falls0.7
10Flathead at Columbia Falls0.7
11Stillwater/Whitefish Rivers1.5
11Stillwater/Whitefish Rivers1.5
12Swan River0.3
12Swan River0.3
13Flathead River at Polson0.7
13Flathead River at Polson0.7
14Mission Valley2.6
14Mission Valley2.6
15Little Bitterroot River-1.5
15Little Bitterroot River-1.5
16Clark above Missoula0.8
16Clark above Missoula0.8
17Blackfoot River0.2
17Blackfoot River0.2
18Clark Fork above Missoula0.3
18Clark Fork above Missoula0.3
19Bitterroot River1.2
19Bitterroot River1.2
20Clark Fork River below Bitterroot River0.5
20Clark Fork River below Bitterroot River0.5
21Clark Fork River below Flathead River0.7
21Clark Fork River below Flathead River0.7
22Beaverhead River-0.7
22Beaverhead River-0.7
23Ruby River2.8
23Ruby River2.8
24Big Hole River1
24Big Hole River1
25Boulder River (Jefferson)1.7
25Boulder River (Jefferson)1.7
26Jefferson River0.7
26Jefferson River0.7
27Madison River2.1
27Madison River2.1
28Gallatin River3.2
28Gallatin River3.2
29Missouri River above Canyon Ferry2
29Missouri River above Canyon Ferry2
30Missouri River below Canyon Ferry2.2
30Missouri River below Canyon Ferry2.2
31Smith River2.4
31Smith River2.4
32Sun River2.4
32Sun River2.4
33Teton River-0.3
33Teton River-0.3
34Birch/Dupuyer1.6
34Birch/Dupuyer1.6
36Musselshell River3.6
36Musselshell River3.6
37Missouri River above Fort Peck3.3
37Missouri River above Fort Peck3.3
38Missouri River below Fort Peck-0.8
38Missouri River below Fort Peck-0.8
39Milk River1.9
39Milk River1.9
41Yellowstone River above Livingston1.7
41Yellowstone River above Livingston1.7
42Shields River3.4
42Shields River3.4
43Boulder River (Yellowstone)1.3
43Boulder River (Yellowstone)1.3
44Stillwater River1.7
44Stillwater River1.7
45Rock/Red Lodge Creeks2.5
45Rock/Red Lodge Creeks2.5
46Clarks Fork River1.7
46Clarks Fork River1.7
47Yellowstone River above Bighorn River1.7
47Yellowstone River above Bighorn River1.7
48Bighorn River below Bighorn Lake1.1
48Bighorn River below Bighorn Lake1.1
49Little Bighorn River2.2
49Little Bighorn River2.2
50Yellowstone River below Bighorn River1.1
50Yellowstone River below Bighorn River1.1
51Tongue River1.9
51Tongue River1.9
52Powder River2.2
52Powder River2.2
999Kootenai at Ft. Steele1.7
999Kootenai at Ft. Steele1.7