June 2008
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 Reservoir1.6
1Marias Above Tiber Reservoir1.6
2Tobacco1.3
2Tobacco1.3
3Kootenai to Libby Dam-0.7
3Kootenai to Libby Dam-0.7
4Kootenai River below Libby Dam0.8
4Kootenai River below Libby Dam0.8
5Fisher River2.5
5Fisher River2.5
6Yaak River1
6Yaak River1
7North FK. Flathead River0.7
7North FK. Flathead River0.7
8Middle FK. Flathead River1.6
8Middle FK. Flathead River1.6
9South FK. Flathead River1.3
9South FK. Flathead River1.3
10Flathead at Columbia Falls1.3
10Flathead at Columbia Falls1.3
12Swan River-0.6
12Swan River-0.6
13Flathead River at Polson1.2
13Flathead River at Polson1.2
14Mission Valley-3.6
14Mission Valley-3.6
15Little Bitterroot River-3.1
15Little Bitterroot River-3.1
16Clark above Missoula1.5
16Clark above Missoula1.5
17Blackfoot River0.5
17Blackfoot River0.5
18Clark Fork above Missoula1.6
18Clark Fork above Missoula1.6
19Bitterroot River1.9
19Bitterroot River1.9
20Clark Fork River below Bitterroot River1.7
20Clark Fork River below Bitterroot River1.7
21Clark Fork River below Flathead River1.4
21Clark Fork River below Flathead River1.4
22Beaverhead River-0.3
22Beaverhead River-0.3
23Ruby River1.1
23Ruby River1.1
24Big Hole River1
24Big Hole River1
25Boulder River (Jefferson)0
25Boulder River (Jefferson)0
26Jefferson River1.6
26Jefferson River1.6
27Madison River1.1
27Madison River1.1
28Gallatin River2
28Gallatin River2
29Missouri River above Canyon Ferry0.5
29Missouri River above Canyon Ferry0.5
30Missouri River below Canyon Ferry0.4
30Missouri River below Canyon Ferry0.4
31Smith River0.3
31Smith River0.3
32Sun River1.4
32Sun River1.4
33Teton River1.1
33Teton River1.1
34Birch/Dupuyer0.7
34Birch/Dupuyer0.7
35Marias Below Tiber Reservoir2.3
35Marias Below Tiber Reservoir2.3
36Musselshell River0.2
36Musselshell River0.2
37Missouri River above Fort Peck1.1
37Missouri River above Fort Peck1.1
38Missouri River below Fort Peck-9.9
38Missouri River below Fort Peck-9.9
39Milk River-0.6
39Milk River-0.6
40Dearborn1.9
40Dearborn1.9
41Yellowstone River above Livingston2.1
41Yellowstone River above Livingston2.1
42Shields River1.7
42Shields River1.7
43Boulder River (Yellowstone)0.6
43Boulder River (Yellowstone)0.6
44Stillwater River0.6
44Stillwater River0.6
45Rock/Red Lodge Creeks0.9
45Rock/Red Lodge Creeks0.9
46Clarks Fork River2.4
46Clarks Fork River2.4
47Yellowstone River above Bighorn River1.8
47Yellowstone River above Bighorn River1.8
48Bighorn River below Bighorn Lake1.5
48Bighorn River below Bighorn Lake1.5
49Little Bighorn River2.1
49Little Bighorn River2.1
50Yellowstone River below Bighorn River1.7
50Yellowstone River below Bighorn River1.7
51Tongue River3.4
51Tongue River3.4
52Powder River3.4
52Powder River3.4
53Upper Judith River2.5
53Upper Judith River2.5
54Saint Mary River1.5
54Saint Mary River1.5