August 2009
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-0.5
1Marias Above Tiber Reservoir-0.5
2Tobacco-0.3
2Tobacco-0.3
3Kootenai to Libby Dam-1.5
3Kootenai to Libby Dam-1.5
4Kootenai River below Libby Dam-2.6
4Kootenai River below Libby Dam-2.6
5Fisher River-0.5
5Fisher River-0.5
6Yaak River-1.6
6Yaak River-1.6
7North FK. Flathead River-0.8
7North FK. Flathead River-0.8
8Middle FK. Flathead River-0.3
8Middle FK. Flathead River-0.3
9South FK. Flathead River0.3
9South FK. Flathead River0.3
10Flathead at Columbia Falls0.3
10Flathead at Columbia Falls0.3
12Swan River-0.2
12Swan River-0.2
13Flathead River at Polson0
13Flathead River at Polson0
14Mission Valley-2.5
14Mission Valley-2.5
15Little Bitterroot River-0.7
15Little Bitterroot River-0.7
16Clark above Missoula1.3
16Clark above Missoula1.3
17Blackfoot River-0.3
17Blackfoot River-0.3
18Clark Fork above Missoula0.3
18Clark Fork above Missoula0.3
19Bitterroot River-0.2
19Bitterroot River-0.2
20Clark Fork River below Bitterroot River0.1
20Clark Fork River below Bitterroot River0.1
21Clark Fork River below Flathead River0
21Clark Fork River below Flathead River0
22Beaverhead River1.7
22Beaverhead River1.7
23Ruby River1.9
23Ruby River1.9
24Big Hole River0.6
24Big Hole River0.6
25Boulder River (Jefferson)2.1
25Boulder River (Jefferson)2.1
26Jefferson River2.2
26Jefferson River2.2
27Madison River0.5
27Madison River0.5
28Gallatin River0.9
28Gallatin River0.9
29Missouri River above Canyon Ferry1.3
29Missouri River above Canyon Ferry1.3
30Missouri River below Canyon Ferry1.2
30Missouri River below Canyon Ferry1.2
31Smith River-0.2
31Smith River-0.2
32Sun River-0.6
32Sun River-0.6
33Teton River-0.8
33Teton River-0.8
34Birch/Dupuyer-0.9
34Birch/Dupuyer-0.9
35Marias Below Tiber Reservoir1.4
35Marias Below Tiber Reservoir1.4
36Musselshell River2.1
36Musselshell River2.1
37Missouri River above Fort Peck1.3
37Missouri River above Fort Peck1.3
38Missouri River below Fort Peck-1.6
38Missouri River below Fort Peck-1.6
39Milk River-0.5
39Milk River-0.5
40Dearborn-0.1
40Dearborn-0.1
41Yellowstone River above Livingston1.3
41Yellowstone River above Livingston1.3
42Shields River1.2
42Shields River1.2
43Boulder River (Yellowstone)1.9
43Boulder River (Yellowstone)1.9
44Stillwater River1.3
44Stillwater River1.3
45Rock/Red Lodge Creeks3
45Rock/Red Lodge Creeks3
46Clarks Fork River1.3
46Clarks Fork River1.3
47Yellowstone River above Bighorn River1.4
47Yellowstone River above Bighorn River1.4
48Bighorn River below Bighorn Lake2.6
48Bighorn River below Bighorn Lake2.6
49Little Bighorn River1.1
49Little Bighorn River1.1
50Yellowstone River below Bighorn River1.9
50Yellowstone River below Bighorn River1.9
51Tongue River3.1
51Tongue River3.1
52Powder River2.3
52Powder River2.3
53Upper Judith River4
53Upper Judith River4
54Saint Mary River-0.5
54Saint Mary River-0.5