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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 Шаблон:Convert of the Шаблон:Convert large project area, all of which was originally intended to be supplied and is still classified irrigable and open for the possible enlargement of the system. Water pumped from the Columbia River is carried over Шаблон:Convert of main canals, stored in a number of reservoirs, then fed into Шаблон:Convert of lateral irrigation canals,[1] and out into Шаблон:Convert of drains and wasteways.[2] 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.[3]
Competing groups lobbied for different irrigation projects; a Spokane group wanted a Шаблон:Convert 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.)[3] 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.
After World War II the project suffered a number of setbacks. Irrigation water began to arrive between 1948 and 1952, but the costs escalated, resulting in the original plan, in which the people receiving irrigation water would pay back the costs of the project over time, being repeatedly revised and becoming a permanent water subsidy. In addition, the original vision of a social engineering project intended to help farmers settle on small landholdings failed. Farm plots, at first restricted in size, became larger and soon became corporate agribusiness operations.[1]
The original plan was that a federal agency similar to the Tennessee Valley Authority would manage the entire system. Instead, conflicts between the Bureau of Reclamation and the Department of Agriculture thwarted the goal of both agencies of settling the project area with small family farms; larger corporate farms arose instead.[1]
The determination to finish the project's plan to irrigate the full Шаблон:Convert waned during the 1960s. The estimated total cost for completing the project had more than doubled between 1940 and 1964, it had become clear that the government's financial investment would not be recovered, and that the benefits of the project were unevenly distributed and increasingly going to larger businesses and corporations. These issues and others dampened enthusiasm for the project, although the exact motives behind the decision to stop construction with the project about half finished are not known.[1]
The Columbia Basin in Central Washington is fertile due to its loess soils, but large portions are a near desert, receiving less than ten inches (254 mm) of rain per year. The area is characterized by huge deposits of flood basalt, thousands of feet thick in places, laid down over a period of approximately 11 million years, during the Miocene epoch.[4] These flood basalts are exposed in some places, while in others they are covered with thick layers of loess.
During the last ice age glaciers shaped the landscape of the Columbia River Plateau. Ice blocked the Columbia River near the north end of Grand Coulee, creating glacial lakes Columbia and Spokane. Ice age glaciers also created Glacial Lake Missoula, in what is now Montana. Erosion allowed glacial Lake Columbia to begin to drain into what became Grand Coulee, which was fully created when glacial Lake Missoula along with glacial Lake Columbia catastrophically emptied.[5] This flood event was one of several known as the Missoula Floods. Unique erosion features, called channeled scablands, are attributed to these amazing floods.
Third Powerhouse (1974) was added as a north wing of the dam from the original Right powerhouse.[7] This addition expanded power generation by 300%.[8]
Grand Coulee Pumping-Generating Plant (1953) consist of 12 pump-turbine units and two reversible pump-turbine units.) The reversible pump-turbines are used to move water from Lake Roosevelt into Banks Lake, from which it can be either sent south into the Columbia Basin Irrigation system or returned to Lake Roosevelt by the generating pumps to create additional electricity for the grid.[6]
Feeder Canal, North and Dry Falls Dams, Banks Lake
Dry Falls, or South Dam, near Coulee City, has a maximum height of Шаблон:Convert and a crest length of Шаблон:Convert. The crest elevation of both dams is Шаблон:Convert. Project water enters Banks Lake through the Feeder Canal from the Pump-generating plant.[6] The outlet for Banks Lake is the Main Canal near Coulee City. It is near the east abutment of Dry Falls Dam.[6] Banks Lake serves as an equalizing reservoir for storage of water for irrigation and can be used to for power generation.
Feeder Canal (1951) links North Dam at northern end of Banks Lake with the siphon outlets for the Grand Coulee Pumping—Generating plants discharge lines. It is Шаблон:Convert long running in an open concrete-lined canal, and a twin-barrel concrete cut—and-cover conduit.[6]
Bacon Tunnel and Siphon (1950) is a Шаблон:Convert long sealed Siphon under the eastern extension of the Dry Falls draw.[6]Файл:Pinto Dam.pngAerial view of Pinto Dam, Washington, USA.
When it was built, Grand Coulee Dam was the largest dam in the world, but it was only part of the irrigation project. Additional dams were built at the north and south ends of Grand Coulee, the dry canyon south of Grand Coulee Dam, allowing the coulee to be filled with water pumped up from the Columbia River. The resulting reservoir, called Banks Lake, is about Шаблон:Convert long. Banks Lake serves as the CBP's initial storage reservoir. Additional canals, siphons, and reservoirs were built south of Bank Lake, reaching over Шаблон:Convert. Water is lifted Шаблон:Convert from Lake Roosevelt to feed the massive network.
The total amount of the Columbia flow that is diverted into the CBP at Grand Coulee varies a little from year to year, and is currently about 3.0 million acre-feet. This is about 3.8 percent of the Columbia's average flow as measured at the Grand Coulee dam.[9] This amount is larger than the combined annual flows of the nearby Yakima,[10] Wenatchee,[11] and Okanogan[12] rivers. There were plans to double the area of irrigated land, according to tour guides at the dam, over the next several decades. However, the Bureau of Reclamation website states that no further development is anticipated, with Шаблон:Convert irrigated out of the original Шаблон:Convert planned.[13]
Interest in completing the Columbia Basin Project's Шаблон:Convert has grown in the late 20th and early 21st centuries. One reason for the renewed interest is the substantial depletion of the Odessa aquifer. Agricultural operations within the CBP's boundaries but outside the developed portion have for decades used groundwater pumped from the Odessa aquifer to irrigate crops.[1]
Hydroelectric power
Hydroelectricity was not the primary goal of the project, but during World War II the demand for electricity in the region boomed. The Hanford nuclear reservation was built just south of the project and aluminum smelting plants flocked to the Columbia Basin. A new power house was built at the Grand Coulee Dam, starting in the late sixties, that tripled the generating capacity. Part of the dam had to be blown up and re-built to make way for the new generators. Electricity is now transmitted to Canada and as far south as San Diego.
Environmental impact
One environmental impact has been the reduction in native fish stocks above the dams. The majority of fish in the Columbia basin are migratory fish like salmon, sturgeon and steelhead. These migratory fish are often harmed or unable to pass through the narrow passages and turbines at dams. In addition to the physical barriers the dams pose, the slowing speed and altered course of the river raises temperatures, alters oxygen content, and changes river bed conditions. These altered conditions can stress and potentially kill both migratory and local non-migratory organisms in the river. The decimation of these migratory fish stocks above Grand Coulee Dam would not allow the former fishing lifestyle of Native Americans of the area, who once depended on the salmon for a way of life.
The environmental impacts of the Columbia Basin Project have made it a contentious and often politicized issue. A common argument for not implementing environmental safeguards at dam sites is that post-construction modifications would likely have to be significant. Tour guides at the Grand Coulee dam site, for example, indicate that a "fish ladder might have to be Шаблон:Convert long to get the fish up the Шаблон:Convert needed, and many fish would die before reaching the upper end" thus no fish ladders were built. Advocates of remedial measures point out that such steps would still be better than the status quo, which has led to marked die-offs and the likely extinction[14] of several types of salmon.
There are a number of issues regarding the runoff of irrigation water. The project region receives about 6 to Шаблон:Convert of annual rainfall, while the application of irrigation water amounts to an equivalent 40 to Шаблон:Convert. The original plans did not sufficiently address the inevitable seepage and runoff.[1] In some cases the results are beneficial. For example, numerous new lakes provide recreation opportunities and habitat for fish and game. In other cases agricultural chemicals in the runoff cause pollution.Шаблон:Citation needed
Economic benefits and costs
The irrigation water provided by this project greatly benefits the agricultural production of the area. North Central Washington is one of the largest and most productive tree fruit producing areas on the planet. Without Coulee Dam and the greater Columbia Basin Project, much of North Central Washington State would be too arid for cultivation.
According to the federal Bureau of Reclamation the yearly value of the Columbia Basin Project is $630 million in irrigated crops, $950 million in power production, $20 million in flood damage prevention, and $50 million in recreation.[15] The project itself involves costs that are difficult to determine. The farms that receive irrigation water must pay for it, but due to insufficient data from the Bureau of Reclamation, it is not possible to compare the total cost paid by the Bureau to the payments received. Nevertheless, the farm payments account for only a small fraction of the total cost to the government, resulting in the project's agricultural corporations receiving a large water subsidy from the government.[1] Critics describe the CBP as a classical example of federal money being used to subsidize a relatively small group of farmers in the American West in places where it would never be economically viable under other circumstances.[1]
↑ 6,06,16,26,36,46,56,66,7Draft Environmental Statement, Columbia Basin Project, Washington; Columbia Basin Project, Ephrata, Washington; Department of the Interior, (INT DES-75-3), Bureau of Reclamation, Department of the Interior; Washington, D.C.; 1975
↑Roise, Charlene (16 September 2014). "Powerhouse: Marcel Breuer at Grand Coulee". docomomo-us. Retrieved 18 July 2017.
↑"Grand Coulee Powerplant". U.S. Bureau of Reclamation. Archived from the original on 29 April 2014. Retrieved 11 March 2015.
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