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<br />Beneath (Iu' Arizona Bridge, (/ spl'cracufar l'icH' a/Hoover Dams Arizona Spifhvay, Juty 1983
<br />
<br />HOIV long did if rake to build the dam,
<br />power plant, and appurtenant works?
<br />Five years. The contractors were allowcd
<br />7 years from April 20, 1931, but con-
<br />crete placemcnl in the dam was COIll-
<br />pleted May 29, 1935, and all features
<br />werc completed by March I, 1936.
<br />
<br />How many men were employed during
<br />the daJn~" cOJlsfmcti011?
<br />An average of 3,500 and a maximum of
<br />5,218, which occurred in June 1934. The
<br />average monthly payroll was $500,000.
<br />
<br />What construction work was lIecessG/Y
<br />before operatioJ/s started or the damsitc?
<br />(1) Construction of Boulder City to house
<br />both Government and contractor em~
<br />ployees. (2) Construction of 7 miles of
<br />22-foot wide, asphalt-surfaced highway
<br />from Boulder City to the damsitc.
<br />(3) Constmction of 22.7 miles of
<br />standard-gauge railroad from the Union
<br />
<br />44
<br />
<br />Pacific main line in Las Vegas to Boulder
<br />City and an additional 10 miles from
<br />Boulder City to thc damsite. (4) Con-
<br />struction of a 222-mile-long power
<br />transmission line from San Bel1lardino,
<br />California, to the damsitc to supply
<br />energy for construction.
<br />
<br />Lake Mead
<br />
<br />What is the elemrion of the reservoir at
<br />high~water?
<br />The high-water line is 1,229 feet above
<br />sea level. At this elevation, the water
<br />would be more than 71/2 feet over the top
<br />of the raised spillway gates. At elevation
<br />1221.4 feet, the water would be at the
<br />top of the raised spillway gates. All lands
<br />below elevation 1,250 have been retained
<br />for reservoir purposes.
<br />
<br />J;Vhat is the reservoirs area?
<br />About 157,900 acres or 247 square miles
<br />at watcr surface elevation 1221.4 feet.
<br />
<br />How long and wide is the reservoir?
<br />At elevation /221.4, Lake Mead extends
<br />approximately 110 miles upstream toward
<br />the Grand Canyon. It also extends about
<br />35 milcs up the Virgin River. The width
<br />varies from several hundred feet in the
<br />canyons to a maximum of 8 miles.
<br />
<br />How much water will Lake Mead hold?
<br />At elevation, 1221.4, it would contain
<br />28,537,000 acre-feet. An acre-foot is the
<br />amount of water required to cover I acre
<br />to a depth of I foot, or approximately
<br />326,000 gallons. The rcservoir will store
<br />the entire average flow of the river for 2
<br />years. That is enough water to cover the
<br />State of Pennsylvania to a depth of one
<br />foot.
<br />
<br />How is the reservoir capacity allotted?
<br />Below elevation 1,229, about 1,500,000
<br />acre-feet of storage capacity is reserved
<br />exclusively for flood control; about
<br />2,378,000 acre-feet for sedimentation con-
<br />trol; about 15,853,000 acre-feet for joint
<br />use (flood control. municipal and in-
<br />dustrial water supply, irrigation, and
<br />power); and 10,024,000 acre-teet for
<br />inactive storage.
<br />
<br />Who operates the dam and reservoir?
<br />The Bureau of Reclamation operates and
<br />maintains the dam, reservoir, penstock
<br />tunnels, intake and outlet works, and
<br />penstocks to, but not including, shutoff
<br />valves at the inlets to the turbine scroll-
<br />case. The National Park Service ad-
<br />ministers Lake Mead as part of the Lake
<br />Mead National Recreation Area.
<br />
<br />How much sediment will be deposited in
<br />the reservoir?
<br />Between 1935 and 1963, about 91,500
<br />acre-feet of sediment was deposited in
<br />Lake Mead each year. With closure of
<br />Glen Canyon Dam, about 370 miles
<br />upstream, the life of Lake Mead is
<br />indefinite.
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