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}} Lock and Dam No. 19 is a lock and dam located on the Upper Mississippi River near Keokuk, Iowa. In 2004, the facility was listed in the National Register of Historic Places as Lock and Dam No. 19 Historic District, #04000179 covering , 7 buildings, 12 structures, 1 object. The lock is owned and operated by the U.S. Army Corps of Engineers. The dam is owned and operated by Ameren Missouri. The lock and dam obliterated the Des Moines Rapids which had effectively been the northern barrier for traffic on the Mississippi until efforts began in 1837 to address the Mississippi's depth in the rapids. ==Locks== The main lock was constructed from 1952 to 1957 and is long and wide with a lift of just over and large enough to handle a full-length tow of barges. It was put into operation in 1957 at a cost of 13.5 million dollars. The 1957 lock replaced a 1910-1913 lock. The 1913 lock was a variant of the standardized Panama canal design and was wide, long and tall with a lift. There was a wide, long and deep dry dock at the site, both the dry dock and 1913 lock were dewatered in 1977 when a sheet pile and cell closure were built blocking the upstream sides of the lock and dry dock.〔(HAER - Mississippi River 9-Foot Channel, Lock & Dam No. 19, Upper Mississippi River, Keokuk, Lee County, IA )〕 With a difference between the normal pool above and below the dam, the lock has the highest "step" in the stairway of the Rock Island District locks and dams. The lock and dam, as well as the rest of the river, can be viewed from a distance on the Observation Deck of the Keokuk Rail Bridge. 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「Lock and Dam No. 19」の詳細全文を読む スポンサード リンク
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