September 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-0.3
1Marias Above Tiber Reservoir-0.3
2Tobacco-0.9
2Tobacco-0.9
3Kootenai to Libby Dam0
3Kootenai to Libby Dam0
4Kootenai River below Libby Dam-1.3
4Kootenai River below Libby Dam-1.3
5Fisher River-0.6
5Fisher River-0.6
6Yaak River-1.7
6Yaak River-1.7
7North FK. Flathead River0
7North FK. Flathead River0
8Middle FK. Flathead River0.3
8Middle FK. Flathead River0.3
9South FK. Flathead River1.2
9South FK. Flathead River1.2
10Flathead at Columbia Falls1.1
10Flathead at Columbia Falls1.1
12Swan River0.1
12Swan River0.1
13Flathead River at Polson-0.4
13Flathead River at Polson-0.4
14Mission Valley0.9
14Mission Valley0.9
15Little Bitterroot River1.7
15Little Bitterroot River1.7
16Clark above Missoula3.2
16Clark above Missoula3.2
17Blackfoot River0.7
17Blackfoot River0.7
18Clark Fork above Missoula2.5
18Clark Fork above Missoula2.5
19Bitterroot River1.5
19Bitterroot River1.5
20Clark Fork River below Bitterroot River2.2
20Clark Fork River below Bitterroot River2.2
21Clark Fork River below Flathead River1.5
21Clark Fork River below Flathead River1.5
22Beaverhead River1.8
22Beaverhead River1.8
23Ruby River1
23Ruby River1
24Big Hole River1.7
24Big Hole River1.7
25Boulder River (Jefferson)3
25Boulder River (Jefferson)3
26Jefferson River2.1
26Jefferson River2.1
27Madison River0.6
27Madison River0.6
28Gallatin River0.9
28Gallatin River0.9
29Missouri River above Canyon Ferry1.9
29Missouri River above Canyon Ferry1.9
30Missouri River below Canyon Ferry1.4
30Missouri River below Canyon Ferry1.4
31Smith River1.7
31Smith River1.7
32Sun River0
32Sun River0
33Teton River0.1
33Teton River0.1
34Birch/Dupuyer-0.9
34Birch/Dupuyer-0.9
35Marias Below Tiber Reservoir1.7
35Marias Below Tiber Reservoir1.7
36Musselshell River3
36Musselshell River3
37Missouri River above Fort Peck1.7
37Missouri River above Fort Peck1.7
38Missouri River below Fort Peck-1.1
38Missouri River below Fort Peck-1.1
39Milk River1.3
39Milk River1.3
40Dearborn3.3
40Dearborn3.3
41Yellowstone River above Livingston0.8
41Yellowstone River above Livingston0.8
42Shields River2.3
42Shields River2.3
43Boulder River (Yellowstone)2.1
43Boulder River (Yellowstone)2.1
44Stillwater River1
44Stillwater River1
45Rock/Red Lodge Creeks3.9
45Rock/Red Lodge Creeks3.9
46Clarks Fork River0.3
46Clarks Fork River0.3
47Yellowstone River above Bighorn River0.9
47Yellowstone River above Bighorn River0.9
48Bighorn River below Bighorn Lake3
48Bighorn River below Bighorn Lake3
49Little Bighorn River0.4
49Little Bighorn River0.4
50Yellowstone River below Bighorn River1.8
50Yellowstone River below Bighorn River1.8
51Tongue River4
51Tongue River4
52Powder River2.9
52Powder River2.9
53Upper Judith River3.8
53Upper Judith River3.8
54Saint Mary River0
54Saint Mary River0