May 2012
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 Reservoir0.6
1Marias Above Tiber Reservoir0.6
2Tobacco2.9
2Tobacco2.9
3Kootenai to Libby Dam2.5
3Kootenai to Libby Dam2.5
4Kootenai River below Libby Dam3.9
4Kootenai River below Libby Dam2.4
4Kootenai River below Libby Dam3.9
4Kootenai River below Libby Dam2.4
6Yaak River3.4
6Yaak River3.4
7North FK. Flathead River2.5
7North FK. Flathead River2.5
8Middle FK. Flathead River2.2
8Middle FK. Flathead River2.2
9South FK. Flathead River4
9South FK. Flathead River4
10Flathead at Columbia Falls3.4
10Flathead at Columbia Falls3.4
11Stillwater/Whitefish Rivers0
11Stillwater/Whitefish Rivers0
12Swan River2.5
12Swan River2.5
13Flathead River at Polson2.7
13Flathead River at Polson2.7
14Mission Valley2.4
14Mission Valley2.4
15Little Bitterroot River2
15Little Bitterroot River2
16Clark above Missoula1
16Clark above Missoula1
17Blackfoot River2.2
17Blackfoot River2.2
18Clark Fork above Missoula1.2
18Clark Fork above Missoula1.2
19Bitterroot River1.8
19Bitterroot River1.8
20Clark Fork River below Bitterroot River1.5
20Clark Fork River below Bitterroot River1.5
21Clark Fork River below Flathead River2.2
21Clark Fork River below Flathead River2.2
22Beaverhead River-0.3
22Beaverhead River-0.3
23Ruby River-0.6
23Ruby River-0.6
24Big Hole River-1
24Big Hole River-1
25Boulder River (Jefferson)0
25Boulder River (Jefferson)0
26Jefferson River0.4
26Jefferson River0.4
27Madison River0.3
27Madison River0.3
28Gallatin River0
28Gallatin River0
29Missouri River above Canyon Ferry0.2
29Missouri River above Canyon Ferry0.2
30Missouri River below Canyon Ferry0.3
30Missouri River below Canyon Ferry0.3
31Smith River2.7
31Smith River2.7
32Sun River1.2
32Sun River1.2
33Teton River1.2
33Teton River1.2
34Birch/Dupuyer1.7
34Birch/Dupuyer1.7
35Marias Below Tiber Reservoir2.2
35Marias Below Tiber Reservoir2.2
36Musselshell River1.6
36Musselshell River1.6
37Missouri River above Fort Peck1.5
37Missouri River above Fort Peck1.5
38Missouri River below Fort Peck0.3
38Missouri River below Fort Peck0.3
39Milk River2
39Milk River2
40Dearborn0.1
40Dearborn0.1
41Yellowstone River above Livingston0.5
41Yellowstone River above Livingston0.5
42Shields River0.8
42Shields River0.8
43Boulder River (Yellowstone)-1
43Boulder River (Yellowstone)-1
44Stillwater River-0.6
44Stillwater River-0.6
45Rock/Red Lodge Creeks-2.2
45Rock/Red Lodge Creeks-2.2
46Clarks Fork River1.7
46Clarks Fork River1.7
47Yellowstone River above Bighorn River0.4
47Yellowstone River above Bighorn River0.4
48Bighorn River below Bighorn Lake-0.8
48Bighorn River below Bighorn Lake-0.8
49Little Bighorn River-0.1
49Little Bighorn River-0.1
50Yellowstone River below Bighorn River-0.2
50Yellowstone River below Bighorn River-0.2
51Tongue River-0.3
51Tongue River-0.3
52Powder River-0.8
52Powder River-0.8
53Upper Judith River-1.2
53Upper Judith River-1.2
54Saint Mary River2.5
54Saint Mary River2.5
999Kootenai at Ft. Steele0
999Kootenai at Ft. Steele0