July 2010
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-0.1
1Marias Above Tiber Reservoir-0.1
2Tobacco-1.9
2Tobacco-1.9
3Kootenai to Libby Dam-2.2
3Kootenai to Libby Dam-2.2
4Kootenai River below Libby Dam-2.5
4Kootenai River below Libby Dam-2.5
5Fisher River-1.8
5Fisher River-1.8
6Yaak River-1.1
6Yaak River-1.1
7North FK. Flathead River-0.3
7North FK. Flathead River-0.3
8Middle FK. Flathead River-1.3
8Middle FK. Flathead River-1.3
9South FK. Flathead River0.3
9South FK. Flathead River0.3
10Flathead at Columbia Falls-0.6
10Flathead at Columbia Falls-0.6
12Swan River1.6
12Swan River1.6
13Flathead River at Polson-0.9
13Flathead River at Polson-0.9
14Mission Valley0
14Mission Valley0
15Little Bitterroot River0
15Little Bitterroot River0
16Clark above Missoula-0.1
16Clark above Missoula-0.1
17Blackfoot River-2.3
17Blackfoot River-2.3
18Clark Fork above Missoula-1.6
18Clark Fork above Missoula-1.6
19Bitterroot River-2
19Bitterroot River-2
20Clark Fork River below Bitterroot River-1.7
20Clark Fork River below Bitterroot River-1.7
21Clark Fork River below Flathead River-1.2
21Clark Fork River below Flathead River-1.2
22Beaverhead River1
22Beaverhead River1
23Ruby River0.3
23Ruby River0.3
24Big Hole River0.7
24Big Hole River0.7
25Boulder River (Jefferson)1.5
25Boulder River (Jefferson)1.5
26Jefferson River1.8
26Jefferson River1.8
27Madison River-1.6
27Madison River-1.6
28Gallatin River-0.2
28Gallatin River-0.2
29Missouri River above Canyon Ferry0
29Missouri River above Canyon Ferry0
30Missouri River below Canyon Ferry0.1
30Missouri River below Canyon Ferry0.1
31Smith River3.3
31Smith River3.3
32Sun River-1.7
32Sun River-1.7
33Teton River-0.3
33Teton River-0.3
34Birch/Dupuyer-0.6
34Birch/Dupuyer-0.6
35Marias Below Tiber Reservoir0
35Marias Below Tiber Reservoir0
36Musselshell River1.6
36Musselshell River1.6
37Missouri River above Fort Peck0.5
37Missouri River above Fort Peck0.5
38Missouri River below Fort Peck-0.2
38Missouri River below Fort Peck-0.2
39Milk River3.6
39Milk River3.6
40Dearborn-1
40Dearborn-1
41Yellowstone River above Livingston-1.8
41Yellowstone River above Livingston-1.8
42Shields River2.5
42Shields River2.5
43Boulder River (Yellowstone)-1.6
43Boulder River (Yellowstone)-1.6
44Stillwater River-1.8
44Stillwater River-1.8
45Rock/Red Lodge Creeks-0.1
45Rock/Red Lodge Creeks-0.1
46Clarks Fork River-2.3
46Clarks Fork River-2.3
47Yellowstone River above Bighorn River-1.9
47Yellowstone River above Bighorn River-1.9
48Bighorn River below Bighorn Lake0.2
48Bighorn River below Bighorn Lake0.2
49Little Bighorn River1
49Little Bighorn River1
50Yellowstone River below Bighorn River-0.9
50Yellowstone River below Bighorn River-0.9
51Tongue River2.4
51Tongue River2.4
52Powder River2.4
52Powder River2.4
53Upper Judith River3.2
53Upper Judith River3.2
54Saint Mary River0.7
54Saint Mary River0.7