Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Modeling of Nearshore-Placed Dredged Material
Movable-bed, large-scale laboratory experiments were conducted at a 1:20 scale to examine the fate and quantify the performance of nearshore-placed dredged material as subaerial and submerged mounds or berms. Three tests were performed for mounds placed at depths representing 1.2 and 3.35 meters and placement onshore. Mound sand was dyed to provide contrast and to differentiate it from the natural sand beach used in the model. Beach surveys were performed intermittently during each 9-hour (prototype) experiment with a laser scanner. In addition to beach change elevations, the scanner provided RGB color components, which enabled tracking of the mound sand. Mound sand dispersed rapidly and was transported mainly downdrift. However, no evidence of appreciable accretion was observed downdrift of the mounds placed offshore. Although the mound sand was transported downdrift, sand accumulation was observed on the beach onshore and updrift of the mounds. Beach response was similar to that of an offshore breakwater in which the mound provides a wave shadow zone to the leeward beach. The mound placed on the foreshore slope accreted in the swash zone directly downdrift of the mound and near the shoreline over the beach length. The experiment demonstrated that nearshore-placed material remains in the surf zone and adds material to the beach face.
Modeling of Nearshore-Placed Dredged Material
Movable-bed, large-scale laboratory experiments were conducted at a 1:20 scale to examine the fate and quantify the performance of nearshore-placed dredged material as subaerial and submerged mounds or berms. Three tests were performed for mounds placed at depths representing 1.2 and 3.35 meters and placement onshore. Mound sand was dyed to provide contrast and to differentiate it from the natural sand beach used in the model. Beach surveys were performed intermittently during each 9-hour (prototype) experiment with a laser scanner. In addition to beach change elevations, the scanner provided RGB color components, which enabled tracking of the mound sand. Mound sand dispersed rapidly and was transported mainly downdrift. However, no evidence of appreciable accretion was observed downdrift of the mounds placed offshore. Although the mound sand was transported downdrift, sand accumulation was observed on the beach onshore and updrift of the mounds. Beach response was similar to that of an offshore breakwater in which the mound provides a wave shadow zone to the leeward beach. The mound placed on the foreshore slope accreted in the swash zone directly downdrift of the mound and near the shoreline over the beach length. The experiment demonstrated that nearshore-placed material remains in the surf zone and adds material to the beach face.
Modeling of Nearshore-Placed Dredged Material
E. R. Smith (Autor:in) / R. Permenter (Autor:in) / M. C. Mohr (Autor:in) / S. A. Chader (Autor:in)
2015
101 pages
Report
Keine Angabe
Englisch
Physical & Chemical Oceanography , Hydrology & Limnology , Solid Wastes Pollution & Control , Coastal regions , Dredged materials , Beaches , Depth , Elevation , Image processing , Models , Ocean currents , Sand , Sediment transport , Surf , Surveys , Nearshore-placed dredged materials , Beneficial uses , Lstf(large-scale sediment transport facility) , Longshore currents , Longshore sediment transport , Movable-bed modeling , Nearshore-placed mounds , Physical modeling , Surf zone processes , Wave breaking , Wave transformation , Beach surveys , Mound sand , Physical models
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