|
New Melones Dam is an earth and rock filled embankment dam on the Stanislaus River, about west of Jamestown, California in the United States. The water impounded by the -tall dam forms New Melones Lake, California's fourth largest reservoir, in the foothills of the Sierra Nevada east of the San Joaquin Valley. The dam serves mainly for irrigation water supply, and also provides hydropower generation, flood control and recreation benefits. New Melones was authorized in 1944 as a unit of the Central Valley Project, a system designed to provide irrigation water to the fertile agricultural region of the Central Valley. The dam would be built by the U.S. Army Corps of Engineers (USACE), and transferred to the U.S. Bureau of Reclamation (USBR) upon completion. In 1966, work began to clear the foundations for a high dam that would replace an earlier structure built by two irrigation districts. Construction of the main embankment began in 1976, and was topped out in late 1978. Water storage in New Melones Lake commenced in 1978, and the dam's hydroelectric station produced its first power in mid-1979. The dam was the focus of a long environmental controversy and was one of the last large dams built in California. Critics protested the flooding of a long scenic stretch of the Stanislaus River, which flowed over whitewater rapids through the deepest limestone canyon in the western United States. The protestors employed a variety of methods, some extreme, to prevent the filling of New Melones Lake until 1983, when record-setting floods filled the reservoir and overflowed the dam's emergency spillway. Because of the controversy in addition to lower-than-expected water yields from the new dam, the USBR has called it "a case study of all that can go wrong with a project." ==Specifications== New Melones Dam and its reservoir comprise the independent New Melones Unit of the Central Valley Project. The dam's primary purpose is to control the runoff from ,〔 or about 92 percent, of the watershed of the Stanislaus River, a major tributary of the San Joaquin River.〔(【引用サイトリンク】url=http://www.usbr.gov/projects/Project.jsp?proj_Name=New%20Melones%20Unit%20Project )〕 At high from the foundations and long, and containing of material, New Melones is the fifth largest embankment dam in California by volume, after Oroville, San Luis, Trinity, and Don Pedro.〔 With a crest elevation of , the dam rises for above the streambed.〔 Flood waters are released through an unlined spillway about a mile (1.6 km) northwest of the dam, with a capacity of .〔 The dam also has a set of outlet works, which can release up to .〔 The impounded water behind the dam forms New Melones Lake, which at full pool of above sea level encompasses of surface water〔 and a volume of .〔 About , 19 percent of the reservoir's capacity, is reserved for flood control. During flooding events, the dam is operated to keep flows on the Stanislaus River below , although this figure may be lowered depending on flow conditions in the San Joaquin River.〔 From 1979 to 1993, the dam and reservoir prevented an estimated $128,500,000 in flood damage.〔 New Melones Dam also serves for water supply and electricity generation. The dam's hydroelectric power plant is located at its base on the north side of the river, and has a rated hydraulic head of .〔 The plant houses two 150.0 MW Francis turbines for a total capacity of 300 MW. Releases are made on a peaking basis and are also dictated by irrigation and flood control requirements below the dam.〔〔 The plant produces about 323 million kilowatt hours annually. By controlling the flows of the Stanislaus River, the dam and reservoir also make available of surplus water each year. Under contract, the dam furnishes an annual to the Stockton East Water District and Central San Joaquin Water Conservation District.〔 The increase in water supply from New Melones Dam has "translated into prosperity for the region, allowing the growth of cities including Tracy and Manteca, and irrigating high-value crops including almonds, walnuts and grapes." 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「New Melones Dam」の詳細全文を読む スポンサード リンク
|