Development of New Coastal Erosion Management Method using Wave Direction Control System(1); New CeM: Tendency of Coastal Erosion and Measures, and Suggestion of New CeM

Abstract

The coastal erosion is largely affected either by construction of port/fishery harbor, or coastal road revetment, which of each breaks the balance of longshore sand transport and one of cross-shore sand transport in coast, respectively. The detached type breakwater have been applied to control longshore sand transport as coastal erosion measures against construction of port/fishery harbor which cause longshore sand transport. However, it also produces new coastal erosion near area. Recently, the artificial reef (A.R.) is almost constructed on the standpoint of landscape as coastal erosion measures in Korea. A.R. is a submerged breakwater with wide crest and had developed to overcome weakness on the detached and submerged breakwaters. The wave is turned into strong longshore current passing through A.R., which occasionally results in scouring erosion around the A.R by increasing the water level at the back of A.R. In this study, we examined the coastal erosion occurrence by port/fishery harbor development and tendency of erosion measures. Also, problems of A.R. are examined with review on research and application example. Based on these, this study proposes new coastal erosion management method, ‘New CeM’, for erosion measure in coast where balance of longshore sand transport is broken. Instead of directly protecting against the ingressive wave, the new method is the wave direction control system for correcting the imbalance of longshore sand transport by obliquely installing breakwater of detached type. The performance and physical phenomenon of New CeM will be introduced later.