Dredging Up

Dredging Up. Fort Peck Dam. , Before the construction of Fort Peck Dam, the water in front of you was land-part of the Missouri River floodplain., More than 125,000,000 cubic yards of soil, enough to fill 12 million dump trucks, was needed to build the world's largest hydraulic-fill earthen dam. Most of the material came from the bottom and sides of the river., Fort Peck Dam rose from sediment sucked from the river bottom by four massive boats called dredges. Each used two huge, 2500-horsepower motors to dig up to 55 feet below the surface and pump the material through miles of floating pipelines to the dam., Using a cutterhead weighing 100 tons, each dredge moved about 2,000 cubic yards of dirt per hour, creating channels called dredge cuts. As the dredges ate away at the shoreline, boomtowns along the river had to be moved., U.S. Army Corps of Engineers. , Preparing the dredge Jefferson to begin dredging operations in the downstream area dredge cut after passing through the swing bridge. August 17, 1937., U.S. Army Corps of Engineers. , Downstream dredge cuts forming in November 1937. The boomtown Park Grove is located in the center right., U.S. Army Corps of Engineers. , Dredging operations often required miles of pipeline. The longest Fort Peck pipeline was a record seven miles. Pumping fill material that far required the help of booster barges. July 1936., Before the dam was closed on June 1937, dredges operated both upstream and downstream of the dam. All cuts made on the upstream side are now hidden below the water of Fort Peck Lake. June 1937., Before Dredging , After Dredging