June 1997
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 Reservoir2.4
1Marias Above Tiber Reservoir2.4
2Tobacco2.5
2Tobacco2.5
3Kootenai to Libby Dam2.7
3Kootenai to Libby Dam2.7
4Kootenai River below Libby Dam0.4
4Kootenai River below Libby Dam0.4
5Fisher River3
5Fisher River3
6Yaak River2.7
6Yaak River2.7
7North FK. Flathead River2.6
7North FK. Flathead River2.6
8Middle FK. Flathead River2.9
8Middle FK. Flathead River2.9
9South FK. Flathead River2.1
9South FK. Flathead River2.1
10Flathead at Columbia Falls2.5
10Flathead at Columbia Falls2.5
11Stillwater/Whitefish Rivers2.5
11Stillwater/Whitefish Rivers2.5
12Swan River2.8
12Swan River2.8
13Flathead River at Polson2.6
13Flathead River at Polson2.6
14Mission Valley1.6
14Mission Valley1.6
15Little Bitterroot River3.2
15Little Bitterroot River3.2
16Clark above Missoula2.2
16Clark above Missoula2.2
17Blackfoot River2.8
17Blackfoot River2.8
18Clark Fork above Missoula2.5
18Clark Fork above Missoula2.5
19Bitterroot River3.1
19Bitterroot River3.1
20Clark Fork River below Bitterroot River2.7
20Clark Fork River below Bitterroot River2.7
21Clark Fork River below Flathead River3.1
21Clark Fork River below Flathead River3.1
22Beaverhead River1.1
22Beaverhead River1.1
23Ruby River1.2
23Ruby River1.2
24Big Hole River2.2
24Big Hole River2.2
25Boulder River (Jefferson)1.7
25Boulder River (Jefferson)1.7
26Jefferson River1.8
26Jefferson River1.8
27Madison River2.8
27Madison River2.8
28Gallatin River2.6
28Gallatin River2.6
29Missouri River above Canyon Ferry2.3
29Missouri River above Canyon Ferry2.3
30Missouri River below Canyon Ferry2.3
30Missouri River below Canyon Ferry2.3
31Smith River2.4
31Smith River2.4
32Sun River2.1
32Sun River2.1
33Teton River2
33Teton River2
34Birch/Dupuyer2
34Birch/Dupuyer2
36Musselshell River1.5
36Musselshell River1.5
37Missouri River above Fort Peck2.2
37Missouri River above Fort Peck2.2
38Missouri River below Fort Peck1.7
38Missouri River below Fort Peck1.7
39Milk River1.8
39Milk River1.8
41Yellowstone River above Livingston2.5
41Yellowstone River above Livingston2.5
42Shields River2.4
42Shields River2.4
43Boulder River (Yellowstone)1.8
43Boulder River (Yellowstone)1.8
44Stillwater River1.3
44Stillwater River1.3
45Rock/Red Lodge Creeks2
45Rock/Red Lodge Creeks2
46Clarks Fork River2.4
46Clarks Fork River2.4
47Yellowstone River above Bighorn River1.9
47Yellowstone River above Bighorn River1.9
48Bighorn River below Bighorn Lake1.7
48Bighorn River below Bighorn Lake1.7
49Little Bighorn River-0.6
49Little Bighorn River-0.6
50Yellowstone River below Bighorn River1.4
50Yellowstone River below Bighorn River1.4
51Tongue River0.1
51Tongue River0.1
52Powder River0.1
52Powder River0.1