Grand Coulee Dam fish ladder, Grand Coulee Dam permanently blocks fish migration, removing over of natural spawning habitat. By largely eliminating anadromous fish above the Okanogan River, the Grand Coulee Dam also set the stage for the subsequent decision not to provide for fish passage at Chief Joseph Dam (built in 1953). Chinook, Steelhead, Sockeye and Coho salmon (as well as other important species including Lamprey) are now unable to spawn in the reaches of the Upper Columbia Basin. The extinction of the spawning grounds upstream from the dam has prevented the Spokane and other tribes from holding the first salmon ceremony. Grand
Grand Coulee volume of water flowing out of the upper coulee. The distribution begins in the uncanyoned basin below Dry Falls and expanded to over a before reaching Quincy Basin. One cataract (Unnamed Coulee) is high and had three alcoves over more than a . There is no channel as the water arrived in a broad sheet. The gravel deposits of Quincy Basin represent only a third or a fourth of the estimated 11 cubic miles of rock excavated from the Grand Coulee and its smaller other related coulees (Dry, Long Lake, Jasper, Lenore, and Unnamed). Most of the debris was carried