August 2010
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
2Tobacco-0.8
2Tobacco-0.8
3Kootenai to Libby Dam-1
3Kootenai to Libby Dam-1
4Kootenai River below Libby Dam-2.5
4Kootenai River below Libby Dam-2.5
5Fisher River-0.6
5Fisher River-0.6
6Yaak River-0.4
6Yaak River-0.4
7North FK. Flathead River0.2
7North FK. Flathead River0.2
8Middle FK. Flathead River-0.7
8Middle FK. Flathead River-0.7
9South FK. Flathead River0.1
9South FK. Flathead River0.1
10Flathead at Columbia Falls0.2
10Flathead at Columbia Falls0.2
12Swan River1.6
12Swan River1.6
13Flathead River at Polson0.3
13Flathead River at Polson0.3
14Mission Valley0
14Mission Valley0
15Little Bitterroot River0
15Little Bitterroot River0
16Clark above Missoula0.5
16Clark above Missoula0.5
17Blackfoot River-1.3
17Blackfoot River-1.3
18Clark Fork above Missoula-0.7
18Clark Fork above Missoula-0.7
19Bitterroot River-1.2
19Bitterroot River-1.2
20Clark Fork River below Bitterroot River-0.8
20Clark Fork River below Bitterroot River-0.8
21Clark Fork River below Flathead River-0.1
21Clark Fork River below Flathead River-0.1
22Beaverhead River2.3
22Beaverhead River2.3
23Ruby River1
23Ruby River1
24Big Hole River-0.3
24Big Hole River-0.3
25Boulder River (Jefferson)2.3
25Boulder River (Jefferson)2.3
26Jefferson River2.8
26Jefferson River2.8
27Madison River0.1
27Madison River0.1
28Gallatin River0.5
28Gallatin River0.5
29Missouri River above Canyon Ferry1
29Missouri River above Canyon Ferry1
30Missouri River below Canyon Ferry1
30Missouri River below Canyon Ferry1
31Smith River2.8
31Smith River2.8
32Sun River-1.1
32Sun River-1.1
33Teton River-0.7
33Teton River-0.7
34Birch/Dupuyer0.1
34Birch/Dupuyer0.1
35Marias Below Tiber Reservoir0
35Marias Below Tiber Reservoir0
36Musselshell River2.6
36Musselshell River2.6
37Missouri River above Fort Peck0
37Missouri River above Fort Peck0
38Missouri River below Fort Peck0.2
38Missouri River below Fort Peck0.2
39Milk River3.8
39Milk River3.8
40Dearborn-0.3
40Dearborn-0.3
41Yellowstone River above Livingston-0.6
41Yellowstone River above Livingston-0.6
42Shields River2.3
42Shields River2.3
43Boulder River (Yellowstone)-0.3
43Boulder River (Yellowstone)-0.3
44Stillwater River0.9
44Stillwater River0.9
45Rock/Red Lodge Creeks2.8
45Rock/Red Lodge Creeks2.8
46Clarks Fork River-1
46Clarks Fork River-1
47Yellowstone River above Bighorn River-0.2
47Yellowstone River above Bighorn River-0.2
48Bighorn River below Bighorn Lake1.2
48Bighorn River below Bighorn Lake1.2
49Little Bighorn River1.3
49Little Bighorn River1.3
50Yellowstone River below Bighorn River0.4
50Yellowstone River below Bighorn River0.4
51Tongue River2.9
51Tongue River2.9
52Powder River2.5
52Powder River2.5
53Upper Judith River3.7
53Upper Judith River3.7
54Saint Mary River1.1
54Saint Mary River1.1