|Council area, Payette National Forest.|
The Weiser River Basin lies in southwestern Idaho. It drains from the Seven Devils Mountains on the north and west, the Cuddy Mountains to the west, and the West Mountains to the east. The drainage flows in a southwesterly direction of about 112 miles where it drains into the Snake River near the City of Weiser. Elevations in the drainage vary from 8,000 feet in the mountains to 2,090 feet at Weiser. The Weiser River drains a basin area of 1,660 square miles, primarily in low, rolling foothills dissected by many small streams. It has an average annual runoff of 742,000 acre-feet of water. Most of the runoff comes during the spring, with extremely low flows during the remainder of the year.
The Weiser River has no mainstem storage reservoirs. Private irrigation districts have constructed four reservoirs on tributary streams. Those reservoirs, Lost Valley, C. Ben Robs, Crane Creek, and Manns Creek, have a total storage capacity of about 83,000 acre-feet of water, and support populations of largemouth bass and crappie. Crane Creek Reservoir contains excellent numbers of white crappie. Lost Valley Reservoir at times is an excellent rainbow trout fishery but has a history of problems associated with stunted yellow perch.
From the mouth of the Weiser River upstream to Galloway Dam, the river supports a marginal warmwater fishery. Low summer flows and poor water quality limit fishery production in this section of river. From Galloway Dam upstream to Cambridge, the river supports a limited fishery of rainbow trout and smallmouth bass. Upstream from Cambridge, rainbow trout and mountain whitefish dominate the fishery. Tributaries to the Weiser River which have not been adversely impacted by agricultural practices or stream alterations support excellent populations of native rainbow/redband trout.Bull trout also exist in some streams within the basin. Bull trout are considered a candidate species for listing under TheEndangered Species Act by the U.S. Fish and Wildlife Service.