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 pumped from the Grand Coulee Dam, into Banks Lake to act as an Equalizing Reservoir and irrigation water source. Evidence of the waterfalls includes a plunge basin where the falls began, immediately south of Coulee City. It contains at least of gravel lower than the open flooring of the land. The river above the falls was shallow and much wider than the gorge. Thus, it wrapped around the lip of the main falls creating lateral falls. These flowed until the recession of the main falls denied them water. Northrup Canyon in Steamboat Rock State Park, contains a dry cataract as