July 2008
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 Reservoir2.7
1Marias Above Tiber Reservoir2.7
2Tobacco1.2
2Tobacco1.2
3Kootenai to Libby Dam0.5
3Kootenai to Libby Dam0.5
4Kootenai River below Libby Dam0.5
4Kootenai River below Libby Dam0.5
5Fisher River2.9
5Fisher River2.9
6Yaak River1.3
6Yaak River1.3
7North FK. Flathead River1.6
7North FK. Flathead River1.6
8Middle FK. Flathead River2.4
8Middle FK. Flathead River2.4
9South FK. Flathead River2.3
9South FK. Flathead River2.3
10Flathead at Columbia Falls2.1
10Flathead at Columbia Falls2.1
12Swan River1.6
12Swan River1.6
13Flathead River at Polson2
13Flathead River at Polson2
14Mission Valley-9.9
14Mission Valley-9.9
15Little Bitterroot River-9.9
15Little Bitterroot River-9.9
16Clark above Missoula1.7
16Clark above Missoula1.7
17Blackfoot River1.2
17Blackfoot River1.2
18Clark Fork above Missoula1.6
18Clark Fork above Missoula1.6
19Bitterroot River2.2
19Bitterroot River2.2
20Clark Fork River below Bitterroot River1.8
20Clark Fork River below Bitterroot River1.8
21Clark Fork River below Flathead River1.9
21Clark Fork River below Flathead River1.9
22Beaverhead River0.1
22Beaverhead River0.1
23Ruby River2.1
23Ruby River2.1
24Big Hole River1.1
24Big Hole River1.1
25Boulder River (Jefferson)1.6
25Boulder River (Jefferson)1.6
26Jefferson River1.7
26Jefferson River1.7
27Madison River0.8
27Madison River0.8
28Gallatin River2.3
28Gallatin River2.3
29Missouri River above Canyon Ferry1
29Missouri River above Canyon Ferry1
30Missouri River below Canyon Ferry1.1
30Missouri River below Canyon Ferry1.1
31Smith River0.7
31Smith River0.7
32Sun River1.8
32Sun River1.8
33Teton River1.5
33Teton River1.5
34Birch/Dupuyer2
34Birch/Dupuyer2
35Marias Below Tiber Reservoir2.9
35Marias Below Tiber Reservoir2.9
36Musselshell River1.2
36Musselshell River1.2
37Missouri River above Fort Peck1.6
37Missouri River above Fort Peck1.6
38Missouri River below Fort Peck-2.8
38Missouri River below Fort Peck-2.8
39Milk River1.8
39Milk River1.8
40Dearborn1.9
40Dearborn1.9
41Yellowstone River above Livingston2.9
41Yellowstone River above Livingston2.9
42Shields River2.6
42Shields River2.6
43Boulder River (Yellowstone)1.6
43Boulder River (Yellowstone)1.6
44Stillwater River0.9
44Stillwater River0.9
45Rock/Red Lodge Creeks0.6
45Rock/Red Lodge Creeks0.6
46Clarks Fork River2.6
46Clarks Fork River2.6
47Yellowstone River above Bighorn River2.4
47Yellowstone River above Bighorn River2.4
48Bighorn River below Bighorn Lake1.3
48Bighorn River below Bighorn Lake1.3
49Little Bighorn River2
49Little Bighorn River2
50Yellowstone River below Bighorn River1.9
50Yellowstone River below Bighorn River1.9
51Tongue River3.3
51Tongue River3.3
52Powder River3.6
52Powder River3.6
53Upper Judith River-1.8
53Upper Judith River-1.8
54Saint Mary River2
54Saint Mary River2