January 2011
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
2Tobacco0.3
2Tobacco0.3
3Kootenai to Libby Dam-0.4
3Kootenai to Libby Dam-0.4
4Kootenai River below Libby Dam0.8
4Kootenai River below Libby Dam0.8
5Fisher River1.1
5Fisher River1.1
6Yaak River0
6Yaak River0
7North FK. Flathead River0.7
7North FK. Flathead River0.7
8Middle FK. Flathead River1.3
8Middle FK. Flathead River1.3
9South FK. Flathead River3.1
9South FK. Flathead River3.1
10Flathead at Columbia Falls1.6
10Flathead at Columbia Falls1.6
12Swan River2.3
12Swan River2.3
13Flathead River at Polson1
13Flathead River at Polson1
14Mission Valley3.2
14Mission Valley3.2
15Little Bitterroot River-2
15Little Bitterroot River-2
16Clark above Missoula0.4
16Clark above Missoula0.4
17Blackfoot River1.8
17Blackfoot River1.8
18Clark Fork above Missoula0
18Clark Fork above Missoula0
20Clark Fork River below Bitterroot River0.9
20Clark Fork River below Bitterroot River0.9
21Clark Fork River below Flathead River1
21Clark Fork River below Flathead River1
22Beaverhead River2
22Beaverhead River2
23Ruby River1.8
23Ruby River1.8
24Big Hole River1.2
24Big Hole River1.2
25Boulder River (Jefferson)0.5
25Boulder River (Jefferson)0.5
26Jefferson River1.9
26Jefferson River1.9
27Madison River1.3
27Madison River1.3
28Gallatin River1
28Gallatin River1
29Missouri River above Canyon Ferry0.9
29Missouri River above Canyon Ferry0.9
30Missouri River below Canyon Ferry0.7
30Missouri River below Canyon Ferry0.7
31Smith River2.3
31Smith River2.3
32Sun River-0.8
32Sun River-0.8
33Teton River0.4
33Teton River0.4
34Birch/Dupuyer-0.4
34Birch/Dupuyer-0.4
35Marias Below Tiber Reservoir1.3
35Marias Below Tiber Reservoir1.3
36Musselshell River1.7
36Musselshell River1.7
37Missouri River above Fort Peck0.8
37Missouri River above Fort Peck0.8
38Missouri River below Fort Peck1
38Missouri River below Fort Peck1
39Milk River2
39Milk River2
40Dearborn-1.1
40Dearborn-1.1
41Yellowstone River above Livingston2
41Yellowstone River above Livingston2
42Shields River2.4
42Shields River2.4
43Boulder River (Yellowstone)2.1
43Boulder River (Yellowstone)2.1
44Stillwater River0.6
44Stillwater River0.6
45Rock/Red Lodge Creeks0.7
45Rock/Red Lodge Creeks0.7
46Clarks Fork River2.1
46Clarks Fork River2.1
47Yellowstone River above Bighorn River1.8
47Yellowstone River above Bighorn River1.8
48Bighorn River below Bighorn Lake0.5
48Bighorn River below Bighorn Lake0.5
49Little Bighorn River-0.5
49Little Bighorn River-0.5
50Yellowstone River below Bighorn River1.2
50Yellowstone River below Bighorn River1.2
51Tongue River-0.6
51Tongue River-0.6
52Powder River-0.3
52Powder River-0.3
53Upper Judith River2.7
53Upper Judith River2.7
54Saint Mary River1.2
54Saint Mary River1.2