October 2011
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
2Tobacco2.3
2Tobacco2.3
3Kootenai to Libby Dam-1.3
3Kootenai to Libby Dam-1.3
4Kootenai River below Libby Dam3.5
4Kootenai River below Libby Dam3.5
5Fisher River3.7
5Fisher River3.7
6Yaak River-0.1
6Yaak River-0.1
7North FK. Flathead River1.6
7North FK. Flathead River1.6
8Middle FK. Flathead River1.8
8Middle FK. Flathead River1.8
9South FK. Flathead River2.3
9South FK. Flathead River2.3
10Flathead at Columbia Falls2.2
10Flathead at Columbia Falls2.2
12Swan River3.5
12Swan River3.5
13Flathead River at Polson2.3
13Flathead River at Polson2.3
14Mission Valley1.2
14Mission Valley1.2
15Little Bitterroot River2.1
15Little Bitterroot River2.1
16Clark above Missoula1.5
16Clark above Missoula1.5
17Blackfoot River2.7
17Blackfoot River2.7
18Clark Fork above Missoula1.9
18Clark Fork above Missoula1.9
19Bitterroot River0.7
19Bitterroot River0.7
20Clark Fork River below Bitterroot River1.6
20Clark Fork River below Bitterroot River1.6
21Clark Fork River below Flathead River2
21Clark Fork River below Flathead River2
22Beaverhead River2.7
22Beaverhead River2.7
23Ruby River0.8
23Ruby River0.8
24Big Hole River1.2
24Big Hole River1.2
25Boulder River (Jefferson)1.2
25Boulder River (Jefferson)1.2
26Jefferson River1.7
26Jefferson River1.7
27Madison River2.3
27Madison River2.3
28Gallatin River-1.2
28Gallatin River-1.2
29Missouri River above Canyon Ferry1.1
29Missouri River above Canyon Ferry1.1
30Missouri River below Canyon Ferry1
30Missouri River below Canyon Ferry1
31Smith River2.8
31Smith River2.8
32Sun River0
32Sun River0
33Teton River0.1
33Teton River0.1
34Birch/Dupuyer1.2
34Birch/Dupuyer1.2
35Marias Below Tiber Reservoir4
35Marias Below Tiber Reservoir4
36Musselshell River2
36Musselshell River2
37Missouri River above Fort Peck1.9
37Missouri River above Fort Peck1.9
38Missouri River below Fort Peck2.4
38Missouri River below Fort Peck2.4
39Milk River2.3
39Milk River2.3
40Dearborn0.8
40Dearborn0.8
41Yellowstone River above Livingston2.9
41Yellowstone River above Livingston2.9
42Shields River-0.1
42Shields River-0.1
43Boulder River (Yellowstone)0.8
43Boulder River (Yellowstone)0.8
44Stillwater River0.7
44Stillwater River0.7
45Rock/Red Lodge Creeks1.2
45Rock/Red Lodge Creeks1.2
46Clarks Fork River1.7
46Clarks Fork River1.7
47Yellowstone River above Bighorn River2.2
47Yellowstone River above Bighorn River2.2
48Bighorn River below Bighorn Lake2
48Bighorn River below Bighorn Lake2
49Little Bighorn River2.6
49Little Bighorn River2.6
50Yellowstone River below Bighorn River2.1
50Yellowstone River below Bighorn River2.1
51Tongue River3.7
51Tongue River3.7
52Powder River1.1
52Powder River1.1
53Upper Judith River2.4
53Upper Judith River2.4
54Saint Mary River0.6
54Saint Mary River0.6