February 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-0.3
1Marias Above Tiber Reservoir-0.3
2Tobacco-0.3
2Tobacco-0.3
3Kootenai to Libby Dam0
3Kootenai to Libby Dam0
4Kootenai River below Libby Dam1.7
4Kootenai River below Libby Dam1.7
5Fisher River0.1
5Fisher River0.1
6Yaak River1
6Yaak River1
7North FK. Flathead River0.1
7North FK. Flathead River0.1
8Middle FK. Flathead River-0.5
8Middle FK. Flathead River-0.5
9South FK. Flathead River-0.3
9South FK. Flathead River-0.3
10Flathead at Columbia Falls0.1
10Flathead at Columbia Falls0.1
11Stillwater/Whitefish Rivers-9.9
11Stillwater/Whitefish Rivers-9.9
12Swan River-1.4
12Swan River-1.4
13Flathead River at Polson-0.9
13Flathead River at Polson-0.9
14Mission Valley-9.9
14Mission Valley-9.9
15Little Bitterroot River-9.9
15Little Bitterroot River-9.9
16Clark above Missoula-0.4
16Clark above Missoula-0.4
17Blackfoot River-0.3
17Blackfoot River-0.3
18Clark Fork above Missoula-0.1
18Clark Fork above Missoula-0.1
19Bitterroot River0.3
19Bitterroot River0.3
20Clark Fork River below Bitterroot River0
20Clark Fork River below Bitterroot River0
21Clark Fork River below Flathead River-0.6
21Clark Fork River below Flathead River-0.6
22Beaverhead River0.4
22Beaverhead River0.4
23Ruby River-0.6
23Ruby River-0.6
24Big Hole River0.6
24Big Hole River0.6
25Boulder River (Jefferson)-1.3
25Boulder River (Jefferson)-1.3
26Jefferson River1.2
26Jefferson River1.2
27Madison River0.8
27Madison River0.8
28Gallatin River1.2
28Gallatin River1.2
29Missouri River above Canyon Ferry0.4
29Missouri River above Canyon Ferry0.4
30Missouri River below Canyon Ferry-0.2
30Missouri River below Canyon Ferry-0.2
31Smith River0.5
31Smith River0.5
32Sun River-0.4
32Sun River-0.4
33Teton River0.4
33Teton River0.4
34Birch/Dupuyer-3.5
34Birch/Dupuyer-3.5
35Marias Below Tiber Reservoir-1.4
35Marias Below Tiber Reservoir-1.4
36Musselshell River-0.6
36Musselshell River-0.6
37Missouri River above Fort Peck-1.1
37Missouri River above Fort Peck-1.1
38Missouri River below Fort Peck-3.4
38Missouri River below Fort Peck-3.4
39Milk River-0.4
39Milk River-0.4
40Dearborn0.2
40Dearborn0.2
41Yellowstone River above Livingston1.7
41Yellowstone River above Livingston1.7
42Shields River0.1
42Shields River0.1
43Boulder River (Yellowstone)0.5
43Boulder River (Yellowstone)0.5
44Stillwater River0.5
44Stillwater River0.5
45Rock/Red Lodge Creeks-3.1
45Rock/Red Lodge Creeks-3.1
46Clarks Fork River2
46Clarks Fork River2
47Yellowstone River above Bighorn River1.4
47Yellowstone River above Bighorn River1.4
48Bighorn River below Bighorn Lake-0.1
48Bighorn River below Bighorn Lake-0.1
49Little Bighorn River-0.3
49Little Bighorn River-0.3
50Yellowstone River below Bighorn River0.7
50Yellowstone River below Bighorn River0.7
51Tongue River0.2
51Tongue River0.2
52Powder River1.8
52Powder River1.8
53Upper Judith River-1.8
53Upper Judith River-1.8
54Saint Mary River1.5
54Saint Mary River1.5