July 2012
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
2Tobacco2.9
2Tobacco2.9
3Kootenai to Libby Dam3.1
3Kootenai to Libby Dam3.1
4Kootenai River below Libby Dam3.9
4Kootenai River below Libby Dam3.9
5Fisher River1.5
5Fisher River1.5
6Yaak River3.2
6Yaak River3.2
7North FK. Flathead River1.6
7North FK. Flathead River1.6
8Middle FK. Flathead River1.8
8Middle FK. Flathead River1.8
9South FK. Flathead River1.3
9South FK. Flathead River1.3
10Flathead at Columbia Falls1.8
10Flathead at Columbia Falls1.8
11Stillwater/Whitefish Rivers0
11Stillwater/Whitefish Rivers0
12Swan River2.5
12Swan River2.5
13Flathead River at Polson1.8
13Flathead River at Polson1.8
14Mission Valley1.1
14Mission Valley1.1
15Little Bitterroot River3.8
15Little Bitterroot River3.8
16Clark above Missoula0.1
16Clark above Missoula0.1
17Blackfoot River1.2
17Blackfoot River1.2
18Clark Fork above Missoula0.6
18Clark Fork above Missoula0.6
19Bitterroot River0.6
19Bitterroot River0.6
20Clark Fork River below Bitterroot River0.6
20Clark Fork River below Bitterroot River0.6
21Clark Fork River below Flathead River1.4
21Clark Fork River below Flathead River1.4
22Beaverhead River-1.1
22Beaverhead River-1.1
23Ruby River-1.3
23Ruby River-1.3
24Big Hole River-0.7
24Big Hole River-0.7
25Boulder River (Jefferson)-0.8
25Boulder River (Jefferson)-0.8
26Jefferson River-0.2
26Jefferson River-0.2
27Madison River-0.5
27Madison River-0.5
28Gallatin River-0.8
28Gallatin River-0.8
29Missouri River above Canyon Ferry-0.1
29Missouri River above Canyon Ferry-0.1
30Missouri River below Canyon Ferry-0.1
30Missouri River below Canyon Ferry-0.1
31Smith River2
31Smith River2
32Sun River0.2
32Sun River0.2
33Teton River-0.3
33Teton River-0.3
34Birch/Dupuyer0.4
34Birch/Dupuyer0.4
35Marias Below Tiber Reservoir0
35Marias Below Tiber Reservoir0
36Musselshell River0.5
36Musselshell River0.5
37Missouri River above Fort Peck0
37Missouri River above Fort Peck0
38Missouri River below Fort Peck0.2
38Missouri River below Fort Peck0.2
39Milk River2.1
39Milk River2.1
40Dearborn-2.2
40Dearborn-2.2
41Yellowstone River above Livingston0.4
41Yellowstone River above Livingston0.4
42Shields River-0.3
42Shields River-0.3
43Boulder River (Yellowstone)-0.5
43Boulder River (Yellowstone)-0.5
44Stillwater River-1
44Stillwater River-1
45Rock/Red Lodge Creeks-3.2
45Rock/Red Lodge Creeks-3.2
46Clarks Fork River1.9
46Clarks Fork River1.9
47Yellowstone River above Bighorn River0.3
47Yellowstone River above Bighorn River0.3
48Bighorn River below Bighorn Lake-1.7
48Bighorn River below Bighorn Lake-1.7
49Little Bighorn River-1.5
49Little Bighorn River-1.5
50Yellowstone River below Bighorn River-0.6
50Yellowstone River below Bighorn River-0.6
51Tongue River-1.7
51Tongue River-1.7
52Powder River-1.4
52Powder River-1.4
53Upper Judith River0.5
53Upper Judith River0.5
54Saint Mary River2.3
54Saint Mary River2.3