January 2009
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 Reservoir-1.8
1Marias Above Tiber Reservoir-1.8
2Tobacco-2.3
2Tobacco-2.3
3Kootenai to Libby Dam-3.4
3Kootenai to Libby Dam-3.4
4Kootenai River below Libby Dam-1.6
4Kootenai River below Libby Dam-1.6
5Fisher River0.2
5Fisher River0.2
6Yaak River-1.7
6Yaak River-1.7
7North FK. Flathead River-3.3
7North FK. Flathead River-3.3
8Middle FK. Flathead River-3.3
8Middle FK. Flathead River-3.3
9South FK. Flathead River-0.2
9South FK. Flathead River-0.2
10Flathead at Columbia Falls-2.3
10Flathead at Columbia Falls-2.3
11Stillwater/Whitefish Rivers-9.9
11Stillwater/Whitefish Rivers-9.9
12Swan River-1.2
12Swan River-1.2
13Flathead River at Polson-2.4
13Flathead River at Polson-2.4
14Mission Valley-1.9
14Mission Valley-1.9
15Little Bitterroot River0.2
15Little Bitterroot River0.2
16Clark above Missoula1.3
16Clark above Missoula1.3
17Blackfoot River0.1
17Blackfoot River0.1
18Clark Fork above Missoula1.4
18Clark Fork above Missoula1.4
19Bitterroot River0.1
19Bitterroot River0.1
20Clark Fork River below Bitterroot River1
20Clark Fork River below Bitterroot River1
21Clark Fork River below Flathead River-1.2
21Clark Fork River below Flathead River-1.2
22Beaverhead River-0.2
22Beaverhead River-0.2
23Ruby River-0.5
23Ruby River-0.5
24Big Hole River0.3
24Big Hole River0.3
25Boulder River (Jefferson)0.7
25Boulder River (Jefferson)0.7
26Jefferson River1.4
26Jefferson River1.4
27Madison River0
27Madison River0
28Gallatin River1
28Gallatin River1
29Missouri River above Canyon Ferry0.2
29Missouri River above Canyon Ferry0.2
30Missouri River below Canyon Ferry-0.3
30Missouri River below Canyon Ferry-0.3
31Smith River0.5
31Smith River0.5
32Sun River-2.3
32Sun River-2.3
33Teton River0.2
33Teton River0.2
34Birch/Dupuyer-2.2
34Birch/Dupuyer-2.2
35Marias Below Tiber Reservoir-1.7
35Marias Below Tiber Reservoir-1.7
36Musselshell River1.2
36Musselshell River1.2
37Missouri River above Fort Peck0
37Missouri River above Fort Peck0
38Missouri River below Fort Peck-2.7
38Missouri River below Fort Peck-2.7
39Milk River0.2
39Milk River0.2
40Dearborn-1.6
40Dearborn-1.6
41Yellowstone River above Livingston0.4
41Yellowstone River above Livingston0.4
42Shields River1.9
42Shields River1.9
43Boulder River (Yellowstone)0.6
43Boulder River (Yellowstone)0.6
44Stillwater River-0.5
44Stillwater River-0.5
45Rock/Red Lodge Creeks0
45Rock/Red Lodge Creeks0
46Clarks Fork River-0.9
46Clarks Fork River-0.9
47Yellowstone River above Bighorn River0.1
47Yellowstone River above Bighorn River0.1
48Bighorn River below Bighorn Lake0.3
48Bighorn River below Bighorn Lake0.3
49Little Bighorn River1
49Little Bighorn River1
50Yellowstone River below Bighorn River0.2
50Yellowstone River below Bighorn River0.2
51Tongue River2.5
51Tongue River2.5
52Powder River1.1
52Powder River1.1
53Upper Judith River1.3
53Upper Judith River1.3
54Saint Mary River0.2
54Saint Mary River0.2