August 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 Reservoir3.1
1Marias Above Tiber Reservoir3.1
2Tobacco1.9
2Tobacco1.9
3Kootenai to Libby Dam1.9
3Kootenai to Libby Dam1.9
4Kootenai River below Libby Dam1.6
4Kootenai River below Libby Dam1.6
5Fisher River0.9
5Fisher River0.9
6Yaak River0.8
6Yaak River0.8
7North FK. Flathead River1.7
7North FK. Flathead River1.7
8Middle FK. Flathead River1.4
8Middle FK. Flathead River1.4
9South FK. Flathead River0.6
9South FK. Flathead River0.6
10Flathead at Columbia Falls1.3
10Flathead at Columbia Falls1.3
11Stillwater/Whitefish Rivers1.9
11Stillwater/Whitefish Rivers1.9
12Swan River-0.1
12Swan River-0.1
13Flathead River at Polson1.1
13Flathead River at Polson1.1
14Mission Valley0.9
14Mission Valley0.9
15Little Bitterroot River-2.5
15Little Bitterroot River-2.5
16Clark above Missoula1.7
16Clark above Missoula1.7
17Blackfoot River0
17Blackfoot River0
18Clark Fork above Missoula0.8
18Clark Fork above Missoula0.8
19Bitterroot River1.7
19Bitterroot River1.7
20Clark Fork River below Bitterroot River1.1
20Clark Fork River below Bitterroot River1.1
21Clark Fork River below Flathead River1.1
21Clark Fork River below Flathead River1.1
22Beaverhead River3.4
22Beaverhead River3.4
23Ruby River2.6
23Ruby River2.6
24Big Hole River3.1
24Big Hole River3.1
25Boulder River (Jefferson)2
25Boulder River (Jefferson)2
26Jefferson River3.1
26Jefferson River3.1
27Madison River1.9
27Madison River1.9
28Gallatin River2.3
28Gallatin River2.3
29Missouri River above Canyon Ferry2.2
29Missouri River above Canyon Ferry2.2
30Missouri River below Canyon Ferry2.2
30Missouri River below Canyon Ferry2.2
31Smith River1.9
31Smith River1.9
32Sun River3.3
32Sun River3.3
33Teton River2.1
33Teton River2.1
34Birch/Dupuyer3.2
34Birch/Dupuyer3.2
36Musselshell River3.6
36Musselshell River3.6
37Missouri River above Fort Peck3.3
37Missouri River above Fort Peck3.3
38Missouri River below Fort Peck1.7
38Missouri River below Fort Peck1.7
39Milk River2.4
39Milk River2.4
41Yellowstone River above Livingston0
41Yellowstone River above Livingston0
42Shields River1.2
42Shields River1.2
43Boulder River (Yellowstone)0.6
43Boulder River (Yellowstone)0.6
44Stillwater River0.9
44Stillwater River0.9
45Rock/Red Lodge Creeks1.3
45Rock/Red Lodge Creeks1.3
46Clarks Fork River-0.1
46Clarks Fork River-0.1
47Yellowstone River above Bighorn River0.1
47Yellowstone River above Bighorn River0.1
48Bighorn River below Bighorn Lake2.1
48Bighorn River below Bighorn Lake2.1
49Little Bighorn River1
49Little Bighorn River1
50Yellowstone River below Bighorn River1.8
50Yellowstone River below Bighorn River1.8
51Tongue River1.4
51Tongue River1.4
52Powder River1.8
52Powder River1.8
999Kootenai at Ft. Steele1.7
999Kootenai at Ft. Steele1.7