낙동강 하구의 해수유동 구조와 사주의 발달과정에 관한 연구

Abstract

The Nakdong River Estuary, which is located in the southern part of Korea, in suffering from many problem, such as variations in sea water circulation, topographical change, generation/disappearance of sandbars and the decrease of water depth, much of these caused by coastal development. In order to setup the management system of sand-bar environment in Nakdong river estuary, hydraulic characteristics and behavior of sediment were investigated. To analyze the behaviors if sediment an in-situ collecting experiment of suspended particulate matters. To examine sediment amount of barrier island, we observed the spatiotemporal variations of sediment transport and quantitatively estimated the accumulation velocity of coastal sediment. For the field survey, we established two survey site off the coasts of Jinu Island and Doyodeung, which had shown rapid variations in sediment amount At these sites, we measured the surface elevation change of the bottom level about 1 month intervals. The sediment pattern showed a significant seasonal variation and was highly influence by the outfall discharge at the Nakdong estuary barrier as well as the incident wave climate. the ENE wave, the most dominant wave throughout the year, moved th sandy sediment toward the front of Jinudo and Doyodeung. For a morphological numerical model, in an area of mixed sedimentary facies of sand and mud, it is required to consider the content of each size fraction. In this study we used EFDC(Environment Fluid Dynamic Code), which enable the consideration of grain size distribution of surface sediment. The result of morphological simulation showed that the incident wave climate, river discharge and tide were the main external force factor affairing the sediment transport pattern.