September 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
2Tobacco4
2Tobacco4
3Kootenai to Libby Dam2.3
3Kootenai to Libby Dam2.3
4Kootenai River below Libby Dam2.2
4Kootenai River below Libby Dam2.2
5Fisher River3.8
5Fisher River3.8
6Yaak River3.2
6Yaak River3.2
7North FK. Flathead River3.8
7North FK. Flathead River3.8
8Middle FK. Flathead River4
8Middle FK. Flathead River4
9South FK. Flathead River1.9
9South FK. Flathead River1.9
10Flathead at Columbia Falls3.2
10Flathead at Columbia Falls3.2
12Swan River4
12Swan River4
13Flathead River at Polson4
13Flathead River at Polson4
14Mission Valley0
14Mission Valley0
15Little Bitterroot River0
15Little Bitterroot River0
16Clark above Missoula3.6
16Clark above Missoula3.6
17Blackfoot River4
17Blackfoot River4
18Clark Fork above Missoula3.9
18Clark Fork above Missoula3.9
19Bitterroot River3.5
19Bitterroot River3.5
20Clark Fork River below Bitterroot River3.8
20Clark Fork River below Bitterroot River3.8
21Clark Fork River below Flathead River3.9
21Clark Fork River below Flathead River3.9
22Beaverhead River3.5
22Beaverhead River3.5
23Ruby River2
23Ruby River2
24Big Hole River2.9
24Big Hole River2.9
25Boulder River (Jefferson)2.6
25Boulder River (Jefferson)2.6
26Jefferson River3.2
26Jefferson River3.2
27Madison River3
27Madison River3
28Gallatin River2.8
28Gallatin River2.8
29Missouri River above Canyon Ferry3
29Missouri River above Canyon Ferry3
30Missouri River below Canyon Ferry2.4
30Missouri River below Canyon Ferry2.4
31Smith River1.8
31Smith River1.8
32Sun River2.4
32Sun River2.4
33Teton River1.6
33Teton River1.6
34Birch/Dupuyer1.4
34Birch/Dupuyer1.4
36Musselshell River2.4
36Musselshell River2.4
37Missouri River above Fort Peck3
37Missouri River above Fort Peck3
38Missouri River below Fort Peck3.2
38Missouri River below Fort Peck3.2
39Milk River1.8
39Milk River1.8
40Dearborn3
40Dearborn3
41Yellowstone River above Livingston3.8
41Yellowstone River above Livingston3.8
42Shields River1.8
42Shields River1.8
43Boulder River (Yellowstone)3.7
43Boulder River (Yellowstone)3.7
44Stillwater River3.1
44Stillwater River3.1
45Rock/Red Lodge Creeks3
45Rock/Red Lodge Creeks3
46Clarks Fork River3.8
46Clarks Fork River3.8
47Yellowstone River above Bighorn River3.7
47Yellowstone River above Bighorn River3.7
48Bighorn River below Bighorn Lake3.8
48Bighorn River below Bighorn Lake3.8
49Little Bighorn River3.3
49Little Bighorn River3.3
50Yellowstone River below Bighorn River3.7
50Yellowstone River below Bighorn River3.7
51Tongue River4
51Tongue River4
52Powder River1.5
52Powder River1.5
54Saint Mary River3.4
54Saint Mary River3.4