Channel Modification for Fish Passage on Umatilla River: Supplement to Final Report 1985

This report summarizes the construction work that was accomplished during the period of June to September 1986 to complete the channel modifications for fish passage in the lower Umatilla River below Threemile Dam. Modifications to the channel were initially designed and constructed by the U.S. Army Corps of Engineers, Walla Walla District (CORPS) under Interagency Agreement No. DE-A179-84-BP15807, Project No. 83-434 dated February 1, 1984. Abnormally high riverflows and other design problems resulted in several construction deficiencies. A review team consisting of representatives of the Oregon Department of Fish and Wildlife (ODFW), Umatilla Insian Tribe, U.S. Bureau of Reclamation (USBR), CORPS, and Bonneville Power Administration (BPA) conducted a field inspection of the modified channel during July 1985. The team identified additional work items necessary to complete the fish passage from the Columbia River to Threemile Dam. The BPA funded the CORPS to complete the design and construction of the project under Interagency Agreement No. DE-A179-86-BP61383, Project 84-343 dated January 23, 1986. The CORPS prepared plans and specifications for completion and awarded a construction contract to Coyote Corporation Contractors and Engineers, Spokane, Washington. Notice to Proceed with the work was given on June 9, 1986. Construction work included rock excavation from existing weirs, concrete weir construction where needed, miscellaneous concrete placement to prevent fish access to dead-end side channels, and construction of two jump pools. A modification to the contract deleted the two jump pools and provided additional channel improvement. The contract was completed on September 5, 1986. The modified channel will now allow the upstream movement of adult anadromous salmonids anticipated in mid-September 1986.