May 2006
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
2Tobacco1.3
2Tobacco1.3
3Kootenai to Libby Dam0.2
3Kootenai to Libby Dam0.2
4Kootenai River below Libby Dam2.9
4Kootenai River below Libby Dam2.9
5Fisher River1
5Fisher River1
6Yaak River0.9
6Yaak River0.9
7North FK. Flathead River-0.8
7North FK. Flathead River-0.8
8Middle FK. Flathead River-0.5
8Middle FK. Flathead River-0.5
9South FK. Flathead River3
9South FK. Flathead River3
10Flathead at Columbia Falls1.1
10Flathead at Columbia Falls1.1
11Stillwater/Whitefish Rivers0.5
11Stillwater/Whitefish Rivers0.5
12Swan River0.9
12Swan River0.9
13Flathead River at Polson0.8
13Flathead River at Polson0.8
14Mission Valley-9.9
14Mission Valley-9.9
15Little Bitterroot River-9.9
15Little Bitterroot River-9.9
16Clark above Missoula0.9
16Clark above Missoula0.9
17Blackfoot River0.4
17Blackfoot River0.4
18Clark Fork above Missoula1.3
18Clark Fork above Missoula1.3
19Bitterroot River1.5
19Bitterroot River1.5
20Clark Fork River below Bitterroot River1.4
20Clark Fork River below Bitterroot River1.4
21Clark Fork River below Flathead River1
21Clark Fork River below Flathead River1
22Beaverhead River-0.6
22Beaverhead River-0.6
23Ruby River0.9
23Ruby River0.9
24Big Hole River0.5
24Big Hole River0.5
25Boulder River (Jefferson)1.4
25Boulder River (Jefferson)1.4
26Jefferson River1.4
26Jefferson River1.4
27Madison River0.8
27Madison River0.8
28Gallatin River1.4
28Gallatin River1.4
29Missouri River above Canyon Ferry0.3
29Missouri River above Canyon Ferry0.3
30Missouri River below Canyon Ferry-0.4
30Missouri River below Canyon Ferry-0.4
31Smith River1.7
31Smith River1.7
32Sun River-0.8
32Sun River-0.8
33Teton River-0.3
33Teton River-0.3
34Birch/Dupuyer-2.8
34Birch/Dupuyer-2.8
35Marias Below Tiber Reservoir-0.5
35Marias Below Tiber Reservoir-0.5
36Musselshell River1.2
36Musselshell River1.2
37Missouri River above Fort Peck-0.9
37Missouri River above Fort Peck-0.9
38Missouri River below Fort Peck-3.4
38Missouri River below Fort Peck-3.4
39Milk River-0.8
39Milk River-0.8
40Dearborn0.3
40Dearborn0.3
41Yellowstone River above Livingston0.8
41Yellowstone River above Livingston0.8
42Shields River2.1
42Shields River2.1
43Boulder River (Yellowstone)0.1
43Boulder River (Yellowstone)0.1
44Stillwater River0.1
44Stillwater River0.1
45Rock/Red Lodge Creeks-2.5
45Rock/Red Lodge Creeks-2.5
46Clarks Fork River-0.9
46Clarks Fork River-0.9
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-2.9
49Little Bighorn River-2.9
50Yellowstone River below Bighorn River-0.1
50Yellowstone River below Bighorn River-0.1
51Tongue River-2.9
51Tongue River-2.9
52Powder River-1
52Powder River-1
53Upper Judith River0.9
53Upper Judith River0.9
54Saint Mary River-1.6
54Saint Mary River-1.6