February 2014
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 River above Tiber Reservoir-1.2
1Marias River above Tiber Reservoir-1.2
2Tobacco River-2.2
2Tobacco River-2.2
3Kootenai Ft. Steele to Libby Dam-1.7
3Kootenai Ft. Steele to Libby Dam-1.7
4Kootenai River below Libby Dam1.4
4Kootenai River below Libby Dam1.4
5Fisher River0.7
5Fisher River0.7
6Yaak River-2.3
6Yaak River-2.3
7North Fk. Flathead River-1.4
7North Fk. Flathead River-1.4
8Middle Fk. Flathead River-0.2
8Middle Fk. Flathead River-0.2
9South Fk. Flathead River2.6
9South Fk. Flathead River2.6
10Flathead River at Columbia Falls0.4
10Flathead River at Columbia Falls0.4
12Swan River1.3
12Swan River1.3
13Flathead River at Polson-0.2
13Flathead River at Polson-0.2
14Mission Valley-0.3
14Mission Valley-0.3
15Little Bitterroot River0.3
15Little Bitterroot River0.3
16Clark Fork River above Milltown1
16Clark Fork River above Milltown1
17Blackfoot River0.1
17Blackfoot River0.1
18Clark Fork River above Missoula0.4
18Clark Fork River above Missoula0.4
19Bitterroot River0
19Bitterroot River0
20Clark Fork River below Bitterroot River0.3
20Clark Fork River below Bitterroot River0.3
21Clark Fork River below Flathead River0
21Clark Fork River below Flathead River0
22Beaverhead River-2.3
22Beaverhead River-2.3
23Ruby River-1.7
23Ruby River-1.7
24Big Hole River-0.2
24Big Hole River-0.2
25Boulder River (Jefferson)-0.1
25Boulder River (Jefferson)-0.1
26Jefferson River0.6
26Jefferson River0.6
27Madison River-1.5
27Madison River-1.5
28Gallatin River-0.2
28Gallatin River-0.2
29Missouri River above Canyon Ferry0.1
29Missouri River above Canyon Ferry0.1
30Missouri River below Canyon Ferry0.1
30Missouri River below Canyon Ferry0.1
31Smith River2.8
31Smith River2.8
32Sun River-1.1
32Sun River-1.1
33Teton River0.2
33Teton River0.2
34Birch/Dupuyer Creeks-2.5
34Birch/Dupuyer Creeks-2.5
35Marias River below Tiber Reservoir-0.2
35Marias River below Tiber Reservoir-0.2
36Musselshell River1.4
36Musselshell River1.4
37Missouri River above Fort Peck0.2
37Missouri River above Fort Peck0.2
38Missouri River below Fort Peck-1.4
38Missouri River below Fort Peck-1.4
39Milk River1.4
39Milk River1.4
40Dearborn River near Craig-1
40Dearborn River near Craig-1
41Yellowstone River above Livingston0.1
41Yellowstone River above Livingston0.1
42Shields River1.5
42Shields River1.5
43Boulder River (Yellowstone)1
43Boulder River (Yellowstone)1
44Stillwater River0
44Stillwater River0
45Rock/Red Lodge Creeks1.5
45Rock/Red Lodge Creeks1.5
46Clarks Fork River0.7
46Clarks Fork River0.7
47Yellowstone River above Bighorn River0.3
47Yellowstone River above Bighorn River0.3
48Bighorn River below Bighorn Lake0.1
48Bighorn River below Bighorn Lake0.1
49Little Bighorn River-0.2
49Little Bighorn River-0.2
50Yellowstone River below Bighorn River0.2
50Yellowstone River below Bighorn River0.2
51Tongue River1.8
51Tongue River1.8
52Powder River2.1
52Powder River2.1
53Upper Judith Basin4
53Upper Judith Basin4
54St. Mary River-0.6
54St. Mary River-0.6