Annual Report of the Chief of Engineers
on Civil Works Activities
Fiscal Year 1974
Department of the Army Corps of Engineers
Extract Report of Walla Walla District

Ririe Lake, Idaho

Location. On Willow Creek, a tributary of Snake River, in Bonneville County, Idaho. The channel improvement extends from junction of Sand and Willow Creeks to a point on Snake River about 4 miles upstream from city of Idaho Falls, Idaho. (See Geological Survey quadrangle map, Ucon, Idaho.) Dam is about 5 miles below confluence of Willow Creek and Meadow Creek and about 15 miles northeast of city of Idaho Falls, Idaho. (See Geological Survey quadrangle map, Poplar, Idaho.)

Existing project. See table 39-B for authorizing legislation. Provides for a rockfill dam about 840 feet long at the crest and about 184 feet high above streambed and downstream channel construction. Spillway will have a concrete-lined channel in right abutment. Outlet works will utilize a reinforced concrete conduit leading from an intake tower upstream to a stilling basin downstream at the toe of left abutment. Lake will have gross storage capacity of 100,000 acre-feet; 90,000 acre-feet of active space for flood control, irrigation, and recreation; and 10,000 acre-feet of space for sediment storage and conservation. Floodway channel will be about 7.5 miles long, with a capacity of 900 cubic feet per second. Authorization specified that the project shall be constructed by the Corps of Engineers and operated and maintained by the Bureau of Reclamation. Estimated Federal cost of new work (July 1974) is $26,930,000, including $30,000 for value of public-owned lands.

Local cooperation. Fully complied with.

Operations and results during fiscal year. A master plan is being prepared by the Bureau of Reclamation. Completion is scheduled for September 1974. Stream diversion began July 1973. A contract for slide gates for the outlet works was completed August 1973. A contract for lake clearing was let October 1973, but operations were suspended during the winter. Combination of a strike by the labor force, bad weather, and unanticipated poor foundation conditions has delayed project completion one year. Main dam construction is about 35 percent complete.

Condition at end of fiscal year. Construction began June 1967. Approximately 89 percent of necessary real estate has been acquired. Entire project is about 45 percent complete. The final Environmental Impact Statement was filed with the Council on Environmental Quality February 13, 1973.