Columbia Basin Irrigation Project
The Columbia Basin Project (or CBP) in Central Washington, United States, is the irrigation network that the Grand Coulee Dam makes possible. It is the largest water reclamation project in the United States, supplying irrigation water to over 670,000 acres (2,700 km2) of the 1,100,000 acres (4,500 km2) large project area, all of which was originally intended to be supplied and is still classified as irrigable and open for the possible enlargement of the system. Water pumped from the Columbia River is carried over 331 miles (533 km) of main canals, stored in a number of reservoirs, then fed into 1,339 miles (2,155 km) of lateral irrigation canals, and out into 3,500 miles (5,600 km) of drains and wasteways. The Grand Coulee Dam, powerplant, and various other parts of the CBP are operated by the Bureau of Reclamation. There are three irrigation districts (the Quincy-Columbia Basin Irrigation District, the East Columbia Basin Irrigation District, and the South Columbia Basin Irrigation District) in the project area, which operate additional local facilities.
The U.S. Bureau of Reclamation was created 1902 to aid development of dry western states. Central Washington's Columbia Plateau was a prime candidate—a desert with fertile loess soil and the Columbia River passing through.
Competing groups lobbied for different irrigation projects; a Spokane group wanted a 134 miles (216 km) gravity flow canal from Lake Pend Oreille while a Wenatchee group (further south) wanted a large dam on the Columbia River, which would pump water up to fill the nearby Grand Coulee, a formerly-dry canyon-like coulee.
After thirteen years of debate, President Franklin D. Roosevelt authorized the dam project with National Industrial Recovery Act money. (It was later specifically authorized by the Rivers and Harbors Act of 1935, and then reauthorized by the Columbia Basin Project Act of 1943 which put it under the Reclamation Project Act of 1939.) Construction of Grand Coulee Dam began in 1933 and was completed in 1942. Its main purpose of pumping water for irrigation was postponed during World War II in favor of electrical power generation that was used for the war effort. Additional hydroelectric generating capacity was added into the 1970s. The Columbia River reservoir behind the dam was named Franklin Delano Roosevelt Lake in honor of the president. The irrigation holding reservoir in Grand Coulee was named Banks Lake.
...
Wikipedia