April 2012
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 Reservoir1.7
1Marias Above Tiber Reservoir1.7
2Tobacco1.7
2Tobacco1.7
3Kootenai to Libby Dam2.5
3Kootenai to Libby Dam2.5
4Kootenai River below Libby Dam4
4Kootenai River below Libby Dam4
5Fisher River1.3
5Fisher River1.3
6Yaak River2.7
6Yaak River2.7
7North FK. Flathead River1.8
7North FK. Flathead River1.8
8Middle FK. Flathead River1.6
8Middle FK. Flathead River1.6
9South FK. Flathead River4
9South FK. Flathead River4
10Flathead at Columbia Falls2.4
10Flathead at Columbia Falls2.4
11Stillwater/Whitefish Rivers0
11Stillwater/Whitefish Rivers0
12Swan River1.2
12Swan River1.2
13Flathead River at Polson1.2
13Flathead River at Polson1.2
14Mission Valley0.8
14Mission Valley0.8
15Little Bitterroot River3
15Little Bitterroot River3
16Clark above Missoula1.1
16Clark above Missoula1.1
17Blackfoot River1.2
17Blackfoot River1.2
18Clark Fork above Missoula1.2
18Clark Fork above Missoula1.2
19Bitterroot River1.2
19Bitterroot River1.2
20Clark Fork River below Bitterroot River1.2
20Clark Fork River below Bitterroot River1.2
21Clark Fork River below Flathead River1.2
21Clark Fork River below Flathead River1.2
22Beaverhead River0.6
22Beaverhead River0.6
23Ruby River-0.6
23Ruby River-0.6
24Big Hole River-0.2
24Big Hole River-0.2
25Boulder River (Jefferson)0.1
25Boulder River (Jefferson)0.1
26Jefferson River1
26Jefferson River1
27Madison River-0.4
27Madison River-0.4
28Gallatin River-0.4
28Gallatin River-0.4
29Missouri River above Canyon Ferry0.2
29Missouri River above Canyon Ferry0.2
30Missouri River below Canyon Ferry-0.6
30Missouri River below Canyon Ferry-0.6
31Smith River3.2
31Smith River3.2
32Sun River1.5
32Sun River1.5
33Teton River1.7
33Teton River1.7
34Birch/Dupuyer2.4
34Birch/Dupuyer2.4
35Marias Below Tiber Reservoir2.5
35Marias Below Tiber Reservoir2.5
36Musselshell River1.3
36Musselshell River1.3
37Missouri River above Fort Peck0.8
37Missouri River above Fort Peck0.8
38Missouri River below Fort Peck0.6
38Missouri River below Fort Peck0.6
39Milk River1.2
39Milk River1.2
40Dearborn1.7
40Dearborn1.7
41Yellowstone River above Livingston0.3
41Yellowstone River above Livingston0.3
42Shields River-0.3
42Shields River-0.3
43Boulder River (Yellowstone)-0.2
43Boulder River (Yellowstone)-0.2
44Stillwater River-0.8
44Stillwater River-0.8
45Rock/Red Lodge Creeks0
45Rock/Red Lodge Creeks0
46Clarks Fork River1.2
46Clarks Fork River1.2
47Yellowstone River above Bighorn River0.2
47Yellowstone River above Bighorn River0.2
48Bighorn River below Bighorn Lake-0.4
48Bighorn River below Bighorn Lake-0.4
49Little Bighorn River1.2
49Little Bighorn River1.2
50Yellowstone River below Bighorn River-0.1
50Yellowstone River below Bighorn River-0.1
51Tongue River1.7
51Tongue River1.7
52Powder River0
52Powder River0
53Upper Judith River2.5
53Upper Judith River2.5
54Saint Mary River2.7
54Saint Mary River2.7
999Kootenai at Ft. Steele0
999Kootenai at Ft. Steele0