Conception, Investigation, and Design of Arrow Dam

The planning and design of Arrow Dam, a major flood control and low-flow augmentation project of the Columbia River Treaty, are described. The subjects covered include the hydraulic studies, which were complicated both by the backwater effects of a major tributary downstream and by a reservoir consisting of two separate lakes under certain flow conditions; extensive hydraulic model studies on energy dissipation and on maintaining satisfactory navigation conditions in the river; deep permeable deposits in the original river channel, which led to the design and construction by dumping through water of a 190-ft-high earth dam with upstream blanket, and to a deep concrete cut-off wall in the cofferdam; a 76-ft-lift navigation lock; and a tightly scheduled construction program to meet the Treaty requirements.