On May 11, 1938, Congress passed the Mitchell Act (external link, Public Law 75-502). The law is intended to mitigate the impacts to fish from water diversions, dams on the mainstem of the Columbia River, pollution and logging. Primarily, though, the mitigation is accomplished through fish hatcheries and the installation of juvenile fish diversion screens at irrigation water withdrawals.
The Mitchell Act included an initial appropriation of $500,000 for surveys and improvements in the Columbia River watershed for the benefit of salmon and steelhead and other anadromous fish. The law and the appropriation recognized that between 1905 and 1931 the federal government had received more than $500,000 in payments from commercial fishers for leasing seining grounds adjacent to Sand Island and Peacock Spit in the Columbia River estuary. Through the authorization, Congress intended to invest money received by the government for the use of fishing grounds in efforts to rebuild and conserve the fish runs. The Act recognized that anadromous fish populations were in a serious decline, and that the decline was caused by impacts on spawning and rearing habitat from deforestation, pollution, hydroelectric dams and diversion of water for irrigation.
The Mitchell Act is an extremely short document for an act of Congress — just one page. Its preamble says it is intended to “provide for the conservation of the fishery resources of the Columbia River, establishment, operation and maintenance of one or more [‘salmon cultural’] stations in Oregon, Washington and Idaho, and for the conduct of necessary investigations, surveys, stream improvements and stocking operations for these purposes.” The Mitchell Act was amended in 1946 to remove funding limitations and authorize federal agencies to utilize state fish and wildlife agencies in Oregon, Washington and Idaho to conserve fishery resources of the region.
The Act also authorized the Secretary of the Interior to conduct investigations and surveys to “direct and facilitate” conservation of the fishery resources of the Columbia River and its tributaries; to construct and install devices in the Columbia River Basin for the improvement of feeding and spawning conditions for fish, for protection of migratory fish from irrigation projects, and for facilitating free migration of fish over obstructions.”
This work was accomplished through the Lower Columbia River Fishery Development Program. In 1956 Congress ordered that the program be implemented above McNary Dam as well as below it. Idaho joined the program in 1957, and the word “Lower” was dropped from the name. Responsibility the program transferred to the U.S. Department of Commerce (National Marine Fisheries Service) in 1970. Today there are 25 Mitchell Act hatcheries in the Columbia Basin — 15 in Washington and 10 in Oregon. The majority are located downstream of Bonneville Dam.