April 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 Reservoir-1.3
1Marias Above Tiber Reservoir-1.3
2Tobacco1.5
2Tobacco1.5
3Kootenai to Libby Dam0.9
3Kootenai to Libby Dam0.9
4Kootenai River below Libby Dam2.5
4Kootenai River below Libby Dam2.5
5Fisher River2.3
5Fisher River2.3
6Yaak River1.6
6Yaak River1.6
7North FK. Flathead River1.2
7North FK. Flathead River1.2
8Middle FK. Flathead River1.3
8Middle FK. Flathead River1.3
9South FK. Flathead River1.3
9South FK. Flathead River1.3
10Flathead at Columbia Falls1.2
10Flathead at Columbia Falls1.2
11Stillwater/Whitefish Rivers-9.9
11Stillwater/Whitefish Rivers-9.9
12Swan River0.1
12Swan River0.1
13Flathead River at Polson1
13Flathead River at Polson1
14Mission Valley-9.9
14Mission Valley-9.9
15Little Bitterroot River-9.9
15Little Bitterroot River-9.9
16Clark above Missoula1.3
16Clark above Missoula1.3
17Blackfoot River0.3
17Blackfoot River0.3
18Clark Fork above Missoula1.5
18Clark Fork above Missoula1.5
19Bitterroot River2
19Bitterroot River2
20Clark Fork River below Bitterroot River1.7
20Clark Fork River below Bitterroot River1.7
21Clark Fork River below Flathead River1.2
21Clark Fork River below Flathead River1.2
22Beaverhead River-0.2
22Beaverhead River-0.2
23Ruby River-0.8
23Ruby River-0.8
24Big Hole River0.4
24Big Hole River0.4
25Boulder River (Jefferson)-1.1
25Boulder River (Jefferson)-1.1
26Jefferson River0.7
26Jefferson River0.7
27Madison River0.7
27Madison River0.7
28Gallatin River1
28Gallatin River1
29Missouri River above Canyon Ferry0.1
29Missouri River above Canyon Ferry0.1
30Missouri River below Canyon Ferry-0.3
30Missouri River below Canyon Ferry-0.3
31Smith River0.9
31Smith River0.9
32Sun River-0.3
32Sun River-0.3
33Teton River0.6
33Teton River0.6
34Birch/Dupuyer-2.9
34Birch/Dupuyer-2.9
35Marias Below Tiber Reservoir-0.2
35Marias Below Tiber Reservoir-0.2
36Musselshell River-1.5
36Musselshell River-1.5
37Missouri River above Fort Peck-0.8
37Missouri River above Fort Peck-0.8
38Missouri River below Fort Peck-3.4
38Missouri River below Fort Peck-3.4
39Milk River-1.9
39Milk River-1.9
40Dearborn0.6
40Dearborn0.6
41Yellowstone River above Livingston2
41Yellowstone River above Livingston2
42Shields River-0.3
42Shields River-0.3
43Boulder River (Yellowstone)0.7
43Boulder River (Yellowstone)0.7
44Stillwater River0.6
44Stillwater River0.6
45Rock/Red Lodge Creeks-3.2
45Rock/Red Lodge Creeks-3.2
46Clarks Fork River2.5
46Clarks Fork River2.5
47Yellowstone River above Bighorn River1.7
47Yellowstone River above Bighorn River1.7
48Bighorn River below Bighorn Lake0.1
48Bighorn River below Bighorn Lake0.1
49Little Bighorn River1.2
49Little Bighorn River1.2
50Yellowstone River below Bighorn River1
50Yellowstone River below Bighorn River1
51Tongue River2.7
51Tongue River2.7
52Powder River2
52Powder River2
53Upper Judith River-2.9
53Upper Judith River-2.9
54Saint Mary River1.2
54Saint Mary River1.2