Dredging Up The Earth To Build A Dam

Dredging Up The Earth To Build A Dam. . Fort Peck Dam is made from Missouri River bottom sands, silts, and clays. This watery mixture of sediments, or slurry, was sucked up from the bottom of the river on both the upstream and downstream sides transported to the dam site through huge pipelines like the one in front of you., Four massive dredges were built: the Missouri, Jefferson, Madison and Gallatin. These 40- by 170-foot boats needed two huge 2500 horsepower motors to dig up to 55 feet below the surface and pump the slurry to the dam. The ladder holding the cutter head weighed 100 tons alone., The dredges were connected to a series of booster pumps that helped pushed the hydraulic fill through as much as nearly seven miles of 28-inch pipe from the river to the dam. The slurry was then pumped into core pools behind the embankment to a height of 240 feet, four times higher than had ever been tried before., The dredges were electrically operated, so there was just as much electrical line stretched to the dredges as pipes, which were supported on pontoons. A great deal of work was involved to move the dredges around, including moving buoys, adding pipe, building the trestles, and anchoring everything down., U.S. Army Corps of Engineers , The stern wheeled towboat, John Ordway, and a derrick boat maneuver the dredge boat, Jefferson (far right) into position. Notice the dredge pipeline and electric feeder line floating on pontoons in the foreground. June 3, 1936., U.S. Army Corps of Engineers , The dredge boat, Jefferson, in operation, Nov. 5, 1938. Compare workers to the size of the cutter head (seven feet in diameter)., U.S. Army Corps of Engineers , Pipelines sometimes ran for miles on dredging operations, June 15, 1937. Notice how far the dredge boats are from the dam area (top center of photo)., U.S. Army Corps of Engineers , Close-up of a dredge pipeline, Feb. 26, 1936.