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Little Rock Dam also known as Littlerock Dam, or officially as Little Rock-Palmdale Dam is a concrete gravity dam on Little Rock Creek in Los Angeles County, California, located about south of Palmdale. The dam and Little Rock Reservoir are owned by the Palmdale Water District and Littlerock Creek Irrigation District, and are used for agricultural and municipal water supply and flood control. The dam is high from foundation to crest and spans across the canyon, forming a reservoir with a capacity of .〔 The reservoir has a surface area of and receives water from a drainage area of on the north slope of the San Gabriel Mountains.〔 A popular recreation spot, the dam, reservoir and vicinity receive about 300,000 visitors each year.〔 Designed by John S. Eastwood, a noted engineer of several dams in the western U.S., Littlerock was originally built in 1924 by the Palmdale Irrigation District (now Palmdale Water District) to provide a water supply for orchards in the area. With a height of and holding of water, it was the tallest multiple-arch reinforced concrete dam in the world at the time. The dam's design combined with its record height was highly controversial; the state mandated renovations in 1932, in which concrete buttresses were added to the dam face.〔 In 1938, the dam nearly failed as a result of historic flooding, which led to the evacuation of hundreds of people in downstream towns. The dam was renovated again in 1966 to comply with increasing safety standards and regional urban development. In the 1970s, it was listed on the National Register of Historic Places (NRHP). In 1994, the last major renovation of the dam was completed, which involved strengthening both faces with roller-compacted concrete, hiding the original multiple arch design forever and transforming it to resemble a conventional gravity dam. The design changes resulted in the dam being taken off the NRHP. The dam was also raised and a new spillway added, increasing the reservoir capacity to its current .〔 ==See also== * List of dams and reservoirs in California 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「Little Rock Dam」の詳細全文を読む スポンサード リンク
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