Analysis of Coastal Erosion in Sanpo-Ri, Uljin-Gun (South Korea) using Field Survey and Measurement Data

Abstract

Several parts of the coastal road in Sanpo-Ri, Uljin-Gun, located in the eastern part of South Korea, have subsided due to erosion and scouring at the bottom of the front face of revetments, caused by frequent high wave attacks. In this study, we carried out field surveys and measurements (including waves, current, water depth, seabed material, beach profile, and shoreline) along the Sanpo-Ri coast and in Namdae-River and Wangpi-River, located in the northern part of Sanpo-Ri, in the summer and winter seasons, in order to analyze and determine the erosion process along the Sanpo-Ri coast. In addition, we used 8 aerial photographs, taken from 1988 to 2013, to analyze long-term coastline changes. The erosion of Sanpo-Ri coast was initiated and progressed not only due to the decreased width of the beach by the construction of coastal roads and the increase of reflected waves at vertical revetments, but also due to the 35 small dams installed in Namdae-River and Wangpi-River since 2000 that have interrupted the sand transport from the rivers to the coast. We performed numerical analyses on the generation of the long-shore current, sand transport, and shoreline change based on field data, and analyzed the erosion process along the Sanpo-Ri coast. These numerical monitoring data and results will be useful to establish coastline maintenance and protection plans on the Sanpoi-Ri coast and on other coasts with erosion problems.