July 2014
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 River above Tiber Reservoir1.8
1Marias River above Tiber Reservoir1.8
2Tobacco River2.1
2Tobacco River2.1
3Kootenai Ft. Steele to Libby Dam1.6
3Kootenai Ft. Steele to Libby Dam1.6
4Kootenai River below Libby Dam1.7
4Kootenai River below Libby Dam1.7
5Fisher River1.2
5Fisher River1.2
6Yaak River1.2
6Yaak River1.2
7North Fk. Flathead River2.5
7North Fk. Flathead River2.5
8Middle Fk. Flathead River2.3
8Middle Fk. Flathead River2.3
9South Fk. Flathead River2.6
9South Fk. Flathead River2.6
10Flathead River at Columbia Falls2.4
10Flathead River at Columbia Falls2.4
12Swan River2.3
12Swan River2.3
13Flathead River at Polson2.4
13Flathead River at Polson2.4
14Mission Valley0.1
14Mission Valley0.1
15Little Bitterroot River3.7
15Little Bitterroot River3.7
16Clark Fork River above Milltown0.9
16Clark Fork River above Milltown0.9
17Blackfoot River2.5
17Blackfoot River2.5
18Clark Fork River above Missoula1.7
18Clark Fork River above Missoula1.7
19Bitterroot River2.3
19Bitterroot River2.3
20Clark Fork River below Bitterroot River1.9
20Clark Fork River below Bitterroot River1.9
21Clark Fork River below Flathead River2.2
21Clark Fork River below Flathead River2.2
22Beaverhead River-1.6
22Beaverhead River-1.6
23Ruby River-1
23Ruby River-1
24Big Hole River1.5
24Big Hole River1.5
25Boulder River (Jefferson)1.7
25Boulder River (Jefferson)1.7
26Jefferson River1.8
26Jefferson River1.8
27Madison River0.1
27Madison River0.1
28Gallatin River1.6
28Gallatin River1.6
29Missouri River above Canyon Ferry0.5
29Missouri River above Canyon Ferry0.5
30Missouri River below Canyon Ferry0.4
30Missouri River below Canyon Ferry0.4
31Smith River2.7
31Smith River2.7
32Sun River1.8
32Sun River1.8
33Teton River0.7
33Teton River0.7
34Birch/Dupuyer Creeks0.8
34Birch/Dupuyer Creeks0.8
35Marias River below Tiber Reservoir2.1
35Marias River below Tiber Reservoir2.1
36Musselshell River1.7
36Musselshell River1.7
37Missouri River above Fort Peck1.1
37Missouri River above Fort Peck1.1
38Missouri River below Fort Peck-0.2
38Missouri River below Fort Peck-0.2
40Dearborn River near Craig0.2
40Dearborn River near Craig0.2
41Yellowstone River above Livingston2.2
41Yellowstone River above Livingston2.2
42Shields River3.1
42Shields River3.1
43Boulder River (Yellowstone)3.5
43Boulder River (Yellowstone)3.5
44Stillwater River2.5
44Stillwater River2.5
45Rock/Red Lodge Creeks2.1
45Rock/Red Lodge Creeks2.1
46Clarks Fork River3.6
46Clarks Fork River3.6
47Yellowstone River above Bighorn River2.6
47Yellowstone River above Bighorn River2.6
48Bighorn River below Bighorn Lake1.2
48Bighorn River below Bighorn Lake1.2
49Little Bighorn River2
49Little Bighorn River2
50Yellowstone River below Bighorn River2
50Yellowstone River below Bighorn River2
51Tongue River2.9
51Tongue River2.9
52Powder River2.4
52Powder River2.4
53Upper Judith Basin0.9
53Upper Judith Basin0.9
54St. Mary River2.7
54St. Mary River2.7