February 2006
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-1.3
1Marias Above Tiber Reservoir-1.3
2Tobacco1.5
2Tobacco1.5
3Kootenai to Libby Dam0.9
3Kootenai to Libby Dam0.9
4Kootenai River below Libby Dam2.2
4Kootenai River below Libby Dam2.2
5Fisher River1.4
5Fisher River1.4
6Yaak River1
6Yaak River1
7North FK. Flathead River0.8
7North FK. Flathead River0.8
8Middle FK. Flathead River0.4
8Middle FK. Flathead River0.4
9South FK. Flathead River3.3
9South FK. Flathead River3.3
10Flathead at Columbia Falls1.6
10Flathead at Columbia Falls1.6
11Stillwater/Whitefish Rivers2.4
11Stillwater/Whitefish Rivers2.4
12Swan River1.1
12Swan River1.1
13Flathead River at Polson1
13Flathead River at Polson1
14Mission Valley-9.9
14Mission Valley-9.9
15Little Bitterroot River-9.9
15Little Bitterroot River-9.9
16Clark above Missoula1.1
16Clark above Missoula1.1
17Blackfoot River0.3
17Blackfoot River0.3
19Bitterroot River1.9
19Bitterroot River1.9
20Clark Fork River below Bitterroot River1.5
20Clark Fork River below Bitterroot River1.5
21Clark Fork River below Flathead River1.2
21Clark Fork River below Flathead River1.2
22Beaverhead River-1.4
22Beaverhead River-1.4
23Ruby River-9.9
23Ruby River-9.9
24Big Hole River0.6
24Big Hole River0.6
25Boulder River (Jefferson)-0.1
25Boulder River (Jefferson)-0.1
26Jefferson River-9.9
26Jefferson River-9.9
27Madison River2.1
27Madison River2.1
28Gallatin River2.2
28Gallatin River2.2
29Missouri River above Canyon Ferry-9.9
29Missouri River above Canyon Ferry-9.9
30Missouri River below Canyon Ferry-9.9
30Missouri River below Canyon Ferry-9.9
31Smith River1.8
31Smith River1.8
32Sun River-1.6
32Sun River-1.6
33Teton River-1.9
33Teton River-1.9
34Birch/Dupuyer-2.9
34Birch/Dupuyer-2.9
35Marias Below Tiber Reservoir0.1
35Marias Below Tiber Reservoir0.1
36Musselshell River-9.9
36Musselshell River-9.9
37Missouri River above Fort Peck-9.9
37Missouri River above Fort Peck-9.9
38Missouri River below Fort Peck-3.4
38Missouri River below Fort Peck-3.4
39Milk River0.2
39Milk River0.2
40Dearborn-0.7
40Dearborn-0.7
41Yellowstone River above Livingston1.4
41Yellowstone River above Livingston1.4
42Shields River2.3
42Shields River2.3
43Boulder River (Yellowstone)2.4
43Boulder River (Yellowstone)2.4
44Stillwater River1.4
44Stillwater River1.4
45Rock/Red Lodge Creeks-1.2
45Rock/Red Lodge Creeks-1.2
46Clarks Fork River0.7
46Clarks Fork River0.7
47Yellowstone River above Bighorn River1.4
47Yellowstone River above Bighorn River1.4
48Bighorn River below Bighorn Lake-0.5
48Bighorn River below Bighorn Lake-0.5
49Little Bighorn River-0.4
49Little Bighorn River-0.4
50Yellowstone River below Bighorn River0.5
50Yellowstone River below Bighorn River0.5
51Tongue River-9.9
51Tongue River-9.9
52Powder River-0.2
52Powder River-0.2