August 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
1Marias Above Tiber Reservoir1
2Tobacco0.5
2Tobacco0.5
3Kootenai to Libby Dam-0.2
3Kootenai to Libby Dam-0.2
4Kootenai River below Libby Dam-1.6
4Kootenai River below Libby Dam-1.6
5Fisher River2.2
5Fisher River2.2
6Yaak River-0.8
6Yaak River-0.8
7North FK. Flathead River0.5
7North FK. Flathead River0.5
8Middle FK. Flathead River2.6
8Middle FK. Flathead River2.6
9South FK. Flathead River0.7
9South FK. Flathead River0.7
10Flathead at Columbia Falls1.1
10Flathead at Columbia Falls1.1
12Swan River2.7
12Swan River2.7
13Flathead River at Polson2.1
13Flathead River at Polson2.1
14Mission Valley0
14Mission Valley0
15Little Bitterroot River-1.6
15Little Bitterroot River-1.6
16Clark above Missoula2.1
16Clark above Missoula2.1
17Blackfoot River1.5
17Blackfoot River1.5
18Clark Fork above Missoula1.9
18Clark Fork above Missoula1.9
19Bitterroot River2.7
19Bitterroot River2.7
20Clark Fork River below Bitterroot River2.1
20Clark Fork River below Bitterroot River2.1
21Clark Fork River below Flathead River2.1
21Clark Fork River below Flathead River2.1
22Beaverhead River-1.2
22Beaverhead River-1.2
23Ruby River2.4
23Ruby River2.4
24Big Hole River1.4
24Big Hole River1.4
25Boulder River (Jefferson)1.6
25Boulder River (Jefferson)1.6
26Jefferson River0.5
26Jefferson River0.5
27Madison River2.2
27Madison River2.2
28Gallatin River3
28Gallatin River3
29Missouri River above Canyon Ferry1.6
29Missouri River above Canyon Ferry1.6
30Missouri River below Canyon Ferry1.8
30Missouri River below Canyon Ferry1.8
31Smith River1.4
31Smith River1.4
32Sun River2.4
32Sun River2.4
33Teton River-0.1
33Teton River-0.1
34Birch/Dupuyer2
34Birch/Dupuyer2
35Marias Below Tiber Reservoir2.1
35Marias Below Tiber Reservoir2.1
36Musselshell River-0.4
36Musselshell River-0.4
37Missouri River above Fort Peck2.1
37Missouri River above Fort Peck2.1
38Missouri River below Fort Peck-2.6
38Missouri River below Fort Peck-2.6
39Milk River1
39Milk River1
40Dearborn1.3
40Dearborn1.3
41Yellowstone River above Livingston3.1
41Yellowstone River above Livingston3.1
42Shields River1.3
42Shields River1.3
43Boulder River (Yellowstone)3.8
43Boulder River (Yellowstone)3.8
44Stillwater River2.7
44Stillwater River2.7
45Rock/Red Lodge Creeks2.4
45Rock/Red Lodge Creeks2.4
46Clarks Fork River3.8
46Clarks Fork River3.8
47Yellowstone River above Bighorn River3.2
47Yellowstone River above Bighorn River3.2
48Bighorn River below Bighorn Lake2.2
48Bighorn River below Bighorn Lake2.2
49Little Bighorn River3.4
49Little Bighorn River3.4
50Yellowstone River below Bighorn River2.8
50Yellowstone River below Bighorn River2.8
51Tongue River3.7
51Tongue River3.7
52Powder River3.4
52Powder River3.4
53Upper Judith River-0.8
53Upper Judith River-0.8
54Saint Mary River2
54Saint Mary River2