Coastline Evolution Analysis and Forecast due to the Construction of Groin at Heoya-River Mouth Area

J. Ocean Eng. Technol. 2008;22(2):28-33.

Kim Seong-Deuk,Kang Kyung-Ho,Park Hae-Sung

Dept. of Civil and Environmental Eng. Ulsan University,Dept. of Civil and Environmental Eng. Ulsan University,Dept. of Civil and Environmental Eng. Ulsan University

회야강 하구방사제 건설에 따른 진하해수욕장 해안선 변화분석 및 예측

김성득,강경호,박해성

울산대학교 건설환경공학부,울산대학교 건설환경공학부,울산대학교 건설환경공학부

Keywords: Heoya-river, Jinha beach, Blockade of river mouth, Groin, Erosion, Tambolo, Submerged breakwater

핵심용어: 회야강, 진하해빈, 하구폐색, 방사제, 침식, 톰볼로, 잠제군

Abstract

From the 1997 to January, 2004, a groin 156m long was constructed at the mouth of the Heoya river-mouth as a protection and barrier. To understand the changes to Jinha beach from the blockade of the river mouth, several aerial photographs, etc., were compared, which showed that the changes were significant. Comparing these results to the state of the area before construction of the groin, the blockade of the river was relaxed, but the formation of the tombolo, in the middle groin area was accelerated and the total Jinha beach erosion and especially the erosion of the southern part of Jinha beach was developed. But according to statements by residents and some current documents, the blockade of the Heoya-river mouth is still underway at the surrounding areas of the groin and chronic dredged sand has been used for littoral nourishment at the northern part of the middle groin and on Jinha beach. The result of numerical simulation based on the present state shows that if this sort of dredging is stopped, the sand accumulation will progress near the river mouth groin and the existing tombolo at the middle groin will progress to the north and severe erosion will occur at the southern coastline near the middle groin and the farthest southern part of Jinha beach, and Jinha beach itself will experience a gradual erosion. The main reason for these erosions should be the typhoons that are happening during the summer season. To provide protection from these kinds of undesirable erosions, a total of 23 numerical simulations have been done. It has been shown that submerged breakwaters at the front area of the beach will be efficient to protect from main beach erosion, but there should be alternative proposals for the influence of the river mouth blockade.