February 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 Reservoir0
1Marias Above Tiber Reservoir0
2Tobacco0.9
2Tobacco0.9
3Kootenai to Libby Dam0.7
3Kootenai to Libby Dam0.7
4Kootenai River below Libby Dam2.1
4Kootenai River below Libby Dam2.1
5Fisher River1.4
5Fisher River1.4
6Yaak River0.5
6Yaak River0.5
7North FK. Flathead River1.9
7North FK. Flathead River1.9
8Middle FK. Flathead River1.7
8Middle FK. Flathead River1.7
9South FK. Flathead River3.7
9South FK. Flathead River3.7
10Flathead at Columbia Falls2.4
10Flathead at Columbia Falls2.4
12Swan River3
12Swan River3
13Flathead River at Polson1.7
13Flathead River at Polson1.7
14Mission Valley2.8
14Mission Valley2.8
15Little Bitterroot River0
15Little Bitterroot River0
16Clark above Missoula1.4
16Clark above Missoula1.4
17Blackfoot River2.3
17Blackfoot River2.3
18Clark Fork above Missoula1.9
18Clark Fork above Missoula1.9
19Bitterroot River0.9
19Bitterroot River0.9
20Clark Fork River below Bitterroot River1.6
20Clark Fork River below Bitterroot River1.6
21Clark Fork River below Flathead River1.7
21Clark Fork River below Flathead River1.7
22Beaverhead River1.4
22Beaverhead River1.4
23Ruby River1.3
23Ruby River1.3
24Big Hole River1.5
24Big Hole River1.5
25Boulder River (Jefferson)0.1
25Boulder River (Jefferson)0.1
26Jefferson River1.9
26Jefferson River1.9
27Madison River0.6
27Madison River0.6
28Gallatin River1.1
28Gallatin River1.1
29Missouri River above Canyon Ferry0.7
29Missouri River above Canyon Ferry0.7
30Missouri River below Canyon Ferry0.6
30Missouri River below Canyon Ferry0.6
31Smith River2.5
31Smith River2.5
32Sun River-0.4
32Sun River-0.4
33Teton River0.7
33Teton River0.7
34Birch/Dupuyer0.8
34Birch/Dupuyer0.8
35Marias Below Tiber Reservoir2
35Marias Below Tiber Reservoir2
36Musselshell River2.2
36Musselshell River2.2
37Missouri River above Fort Peck1
37Missouri River above Fort Peck1
38Missouri River below Fort Peck0.9
38Missouri River below Fort Peck0.9
39Milk River2.2
39Milk River2.2
40Dearborn-0.3
40Dearborn-0.3
41Yellowstone River above Livingston1.8
41Yellowstone River above Livingston1.8
42Shields River2.5
42Shields River2.5
43Boulder River (Yellowstone)2.2
43Boulder River (Yellowstone)2.2
44Stillwater River0.6
44Stillwater River0.6
45Rock/Red Lodge Creeks-0.9
45Rock/Red Lodge Creeks-0.9
46Clarks Fork River2.4
46Clarks Fork River2.4
47Yellowstone River above Bighorn River1.7
47Yellowstone River above Bighorn River1.7
48Bighorn River below Bighorn Lake-2
48Bighorn River below Bighorn Lake-2
49Little Bighorn River0.2
49Little Bighorn River0.2
50Yellowstone River below Bighorn River0
50Yellowstone River below Bighorn River0
51Tongue River1.6
51Tongue River1.6
52Powder River1.3
52Powder River1.3
53Upper Judith River3.3
53Upper Judith River3.3
54Saint Mary River1.9
54Saint Mary River1.9