BEACH CHANGES AROUND DAWU FISHING PORT IN TAIWAN CAUSED BY OBSTRUCTION OF LONGSHORE SAND TRANSPORT AND MEASURES

Takayuki Kumada, Takaaki Uda, Jimmy J. Y. Liu

Abstract


The Dawu fishing port breakwater has been extending since 1956 in Taitung City located in the southeast part of Taiwan, obstructing southward longshore sand transport. Because of the blockage of longshore sand transport at this fishing port, severe downcoast erosion occurred, resulting in the wave overtopping damage to Route No. 9 extending along the coastline, and urgent measures were required to enhance the safety of the route. As measures, beach nourishment using coarse materials including gravel produced from the construction of a road tunnel was planned, as well as the construction of groins on the downcoast. We first analyzed beach changes around this fishing port using past aerial photographs and bathymetric survey data, and beach changes were reproduced using the contour-line-change model considering changes in grain size. Then, the effect of measures was investigated using the model.

Keywords


beach erosion; Taiwan; Dawu fishing port; longshore sand transport; obstruction; contour-line-change model

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