August 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 Reservoir3.8
1Marias Above Tiber Reservoir3.8
2Tobacco4
2Tobacco4
3Kootenai to Libby Dam3.9
3Kootenai to Libby Dam3.9
4Kootenai River below Libby Dam3.2
4Kootenai River below Libby Dam3.2
5Fisher River3.9
5Fisher River3.9
6Yaak River4
6Yaak River4
7North FK. Flathead River4
7North FK. Flathead River4
8Middle FK. Flathead River4
8Middle FK. Flathead River4
9South FK. Flathead River4
9South FK. Flathead River4
10Flathead at Columbia Falls4
10Flathead at Columbia Falls4
12Swan River4
12Swan River4
13Flathead River at Polson4
13Flathead River at Polson4
14Mission Valley0
14Mission Valley0
15Little Bitterroot River0
15Little Bitterroot River0
16Clark above Missoula4
16Clark above Missoula4
17Blackfoot River4
17Blackfoot River4
18Clark Fork above Missoula4
18Clark Fork above Missoula4
19Bitterroot River4
19Bitterroot River4
20Clark Fork River below Bitterroot River4
20Clark Fork River below Bitterroot River4
21Clark Fork River below Flathead River4
21Clark Fork River below Flathead River4
22Beaverhead River3.5
22Beaverhead River3.5
23Ruby River2.8
23Ruby River2.8
24Big Hole River4
24Big Hole River4
25Boulder River (Jefferson)3.7
25Boulder River (Jefferson)3.7
26Jefferson River4
26Jefferson River4
27Madison River4
27Madison River4
28Gallatin River4
28Gallatin River4
29Missouri River above Canyon Ferry3.9
29Missouri River above Canyon Ferry3.9
30Missouri River below Canyon Ferry4
30Missouri River below Canyon Ferry4
31Smith River4
31Smith River4
32Sun River4
32Sun River4
33Teton River3.4
33Teton River3.4
34Birch/Dupuyer2.9
34Birch/Dupuyer2.9
35Marias Below Tiber Reservoir4
35Marias Below Tiber Reservoir4
36Musselshell River3.1
36Musselshell River3.1
37Missouri River above Fort Peck4
37Missouri River above Fort Peck4
38Missouri River below Fort Peck3.5
38Missouri River below Fort Peck3.5
39Milk River2.5
39Milk River2.5
40Dearborn3.4
40Dearborn3.4
41Yellowstone River above Livingston4
41Yellowstone River above Livingston4
42Shields River3.8
42Shields River3.8
43Boulder River (Yellowstone)4
43Boulder River (Yellowstone)4
44Stillwater River3.9
44Stillwater River3.9
45Rock/Red Lodge Creeks3.6
45Rock/Red Lodge Creeks3.6
46Clarks Fork River4
46Clarks Fork River4
47Yellowstone River above Bighorn River4
47Yellowstone River above Bighorn River4
48Bighorn River below Bighorn Lake4
48Bighorn River below Bighorn Lake4
49Little Bighorn River4
49Little Bighorn River4
50Yellowstone River below Bighorn River4
50Yellowstone River below Bighorn River4
51Tongue River4
51Tongue River4
52Powder River3.9
52Powder River3.9
53Upper Judith River0
53Upper Judith River0
54Saint Mary River3.9
54Saint Mary River3.9