Columbia Basin Project
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The Columbia Basin Project is an irrigation project in Central Washington, USA. It provides water for over 600,000 acres (2,400 km²) of agriculture.
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[edit] History
The U.S. Bureau of Reclamation was created 1902 to aid development of dry western states. Central Washington's Columbia River 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 mile (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. Construction of the 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 part of the project began operation in 1951.
[edit] Geology
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.[1] 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.[2] This flood event was one of several known as the Missoula Floods. Unique erosion features, called channeled scablands, are attributed to these amazing floods.
[edit] Irrigation of the Columbia Basin
The Grand Coulee Dam was the largest dam in the world when it was built, but it was only part of the irrigation project. Grand Coulee had small dams added that turned part of it into the thirty mile (50 km) long Banks Lake. This was the first leg of storage and distribution for the water. Additional canals, siphons and lakes were built for a hundred miles (160 km) south of the dam.
Water is lifted 280 feet (85 m) from Lake Roosevelt to feed the massive network. Some of the spring runoff is stored in this network for use throughout the growing season.
Between 2 and 3% of the Columbia's flow is currently diverted at the Grand Coulee Dam. There are 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 671,000 acres (2,720 km²) irrigated out of the original 1.1 million acres (4,450 km²) planned.
[edit] Economic Value
Annual values from the U.S. Bureau of Reclamation;
- Irrigated crops: $630 million
- Power produced: $950 million
- Flood damage prevented: $20 million
- Recreation: 3 million visits - $50 million
[edit] Unintended benefits
Hydroelectricity was never the primary goal of the project. There was no use at the time for the massive amounts of power available from the Columbia. World War II changed all that. 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 shipped to Canada and as far south as San Diego.
The numerous new lakes provide all types of water recreation and new habitat was created for fish and game.
[edit] Environmental consequences
The most prominent negative environmental impact has been the decimation of 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 destroyed, or unable to pass through, the narrow passages and turbines at dams. Fish ladders, although technically possible at each of the Columbia Basin dams, are often not present. 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 further stress or kill both migratory and local non-migratory organisms in the river. The decimation of these migratory fish stocks has been especially dire for many of the Native Americans of the Pacific Northwest who depended on the salmon for a way of life.
The significant negative 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 5 miles (8.0 km) long to get the fish up the 550 feet (170 m) 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[3] of several types of salmon.
[edit] See also
- Tributaries of the Columbia River
- Cities on the Columbia River
- Hydroelectric dams on the Columbia River
- Cascades Rapids
[edit] References
- Orr, Elizabeth L. and William N. Orr (1996) Geology of the Pacific Northwest, The McGraw-Hill Companies
- West Coast Salmon Biological Review Team (2003) "Updated Status of Federally Listed ESUs of West Coast Salmon and Steelhead" National Marine Fisheries Service
[edit] Notes
[edit] External links
- History of the Columbia Basin Project
- History of the CBP from the Northwest Power and Conservation Council
- Official Website
- Official explanation of Salmon Recovery and Salmon Death-minimizing activities required by the Endangered Species Act
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