February 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 Reservoir1.9
1Marias Above Tiber Reservoir1.9
2Tobacco2.4
2Tobacco2.4
3Kootenai to Libby Dam1.8
3Kootenai to Libby Dam1.8
4Kootenai River below Libby Dam2.3
4Kootenai River below Libby Dam2.3
5Fisher River1.9
5Fisher River1.9
6Yaak River1.2
6Yaak River1.2
7North FK. Flathead River2.3
7North FK. Flathead River2.3
8Middle FK. Flathead River2
8Middle FK. Flathead River2
9South FK. Flathead River2.2
9South FK. Flathead River2.2
10Flathead at Columbia Falls2.3
10Flathead at Columbia Falls2.3
11Stillwater/Whitefish Rivers2.7
11Stillwater/Whitefish Rivers2.7
12Swan River2
12Swan River2
13Flathead River at Polson2.5
13Flathead River at Polson2.5
14Mission Valley1.7
14Mission Valley1.7
15Little Bitterroot River0.7
15Little Bitterroot River0.7
16Clark above Missoula1.9
16Clark above Missoula1.9
17Blackfoot River1.9
17Blackfoot River1.9
18Clark Fork above Missoula1.9
18Clark Fork above Missoula1.9
19Bitterroot River2.8
19Bitterroot River2.8
20Clark Fork River below Bitterroot River2.6
20Clark Fork River below Bitterroot River2.6
21Clark Fork River below Flathead River2.5
21Clark Fork River below Flathead River2.5
22Beaverhead River2.1
22Beaverhead River2.1
23Ruby River1.1
23Ruby River1.1
24Big Hole River2.7
24Big Hole River2.7
25Boulder River (Jefferson)0.8
25Boulder River (Jefferson)0.8
26Jefferson River2.2
26Jefferson River2.2
27Madison River2.2
27Madison River2.2
28Gallatin River1.8
28Gallatin River1.8
29Missouri River above Canyon Ferry2.4
29Missouri River above Canyon Ferry2.4
30Missouri River below Canyon Ferry2.2
30Missouri River below Canyon Ferry2.2
31Smith River1.7
31Smith River1.7
32Sun River1.9
32Sun River1.9
33Teton River1.9
33Teton River1.9
34Birch/Dupuyer2.4
34Birch/Dupuyer2.4
36Musselshell River1.3
36Musselshell River1.3
37Missouri River above Fort Peck2.5
37Missouri River above Fort Peck2.5
38Missouri River below Fort Peck1.6
38Missouri River below Fort Peck1.6
39Milk River1.6
39Milk River1.6
41Yellowstone River above Livingston2.9
41Yellowstone River above Livingston2.9
42Shields River0.8
42Shields River0.8
43Boulder River (Yellowstone)2.3
43Boulder River (Yellowstone)2.3
44Stillwater River2.2
44Stillwater River2.2
45Rock/Red Lodge Creeks2.1
45Rock/Red Lodge Creeks2.1
46Clarks Fork River2.6
46Clarks Fork River2.6
47Yellowstone River above Bighorn River2.6
47Yellowstone River above Bighorn River2.6
48Bighorn River below Bighorn Lake2.2
48Bighorn River below Bighorn Lake2.2
49Little Bighorn River0
49Little Bighorn River0
50Yellowstone River below Bighorn River2.4
50Yellowstone River below Bighorn River2.4
51Tongue River0.6
51Tongue River0.6
52Powder River0.6
52Powder River0.6