Physical impact on the reclamation area resulting from offshore dredging at the Changhwa coast, Taiwan

The physical impact of offshore dredging on the reclamation area at the Cha nghwa coast, Taiwan, is investigated using a three-dimensional movable-bed model test. A distorted modeling law consisting of maintaining similarity o f the equilibrium beach profile between the model and prototype is proposed . The geometric distortion was verified through a series of preliminary exp eriments conducted in a wave flume. Experimental results show that the dist orted modeling is able to reproduce the beach-face slope in nature. An appr opriate long-term morphological time-scale was determined based on a compar ison of model longshore littoral transport rates and equivalent prototype v alues. Seabed topographical changes before and after offshore dredging are evaluated in model tests. A suitable countermeasure to prevent beach erosio n from wave attack along the reclamation area is suggested from the experim ental results. (C) 2000 Elsevier Science Ltd. All rights reserved.