July 1999
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 Reservoir-1.6
1Marias Above Tiber Reservoir-1.6
2Tobacco1.6
2Tobacco1.6
3Kootenai to Libby Dam0.3
3Kootenai to Libby Dam0.3
4Kootenai River below Libby Dam-1.1
4Kootenai River below Libby Dam-1.1
5Fisher River1.9
5Fisher River1.9
6Yaak River2.3
6Yaak River2.3
7North FK. Flathead River0.5
7North FK. Flathead River0.5
8Middle FK. Flathead River0.1
8Middle FK. Flathead River0.1
9South FK. Flathead River0.9
9South FK. Flathead River0.9
10Flathead at Columbia Falls0.5
10Flathead at Columbia Falls0.5
11Stillwater/Whitefish Rivers-0.1
11Stillwater/Whitefish Rivers-0.1
12Swan River-0.6
12Swan River-0.6
13Flathead River at Polson0.3
13Flathead River at Polson0.3
14Mission Valley-0.5
14Mission Valley-0.5
15Little Bitterroot River0.8
15Little Bitterroot River0.8
16Clark above Missoula-0.1
16Clark above Missoula-0.1
17Blackfoot River0.6
17Blackfoot River0.6
18Clark Fork above Missoula0.3
18Clark Fork above Missoula0.3
19Bitterroot River0.6
19Bitterroot River0.6
20Clark Fork River below Bitterroot River0.4
20Clark Fork River below Bitterroot River0.4
21Clark Fork River below Flathead River0.3
21Clark Fork River below Flathead River0.3
22Beaverhead River1.4
22Beaverhead River1.4
23Ruby River0.6
23Ruby River0.6
24Big Hole River0
24Big Hole River0
25Boulder River (Jefferson)-1
25Boulder River (Jefferson)-1
26Jefferson River0.6
26Jefferson River0.6
27Madison River-0.2
27Madison River-0.2
28Gallatin River0
28Gallatin River0
29Missouri River above Canyon Ferry0.1
29Missouri River above Canyon Ferry0.1
30Missouri River below Canyon Ferry0.6
30Missouri River below Canyon Ferry0.6
31Smith River-2
31Smith River-2
32Sun River-0.7
32Sun River-0.7
33Teton River-0.7
33Teton River-0.7
34Birch/Dupuyer-1.9
34Birch/Dupuyer-1.9
36Musselshell River-0.2
36Musselshell River-0.2
37Missouri River above Fort Peck0.5
37Missouri River above Fort Peck0.5
38Missouri River below Fort Peck0.1
38Missouri River below Fort Peck0.1
39Milk River0.6
39Milk River0.6
41Yellowstone River above Livingston1
41Yellowstone River above Livingston1
42Shields River-1.8
42Shields River-1.8
43Boulder River (Yellowstone)0.3
43Boulder River (Yellowstone)0.3
44Stillwater River-0.7
44Stillwater River-0.7
45Rock/Red Lodge Creeks-0.7
45Rock/Red Lodge Creeks-0.7
46Clarks Fork River0
46Clarks Fork River0
47Yellowstone River above Bighorn River0.5
47Yellowstone River above Bighorn River0.5
48Bighorn River below Bighorn Lake1.1
48Bighorn River below Bighorn Lake1.1
49Little Bighorn River0.4
49Little Bighorn River0.4
50Yellowstone River below Bighorn River0.9
50Yellowstone River below Bighorn River0.9
51Tongue River1.6
51Tongue River1.6
52Powder River1.9
52Powder River1.9
999Kootenai at Ft. Steele-1.9
999Kootenai at Ft. Steele-1.9