한반도 서해 천수만에서 해안선 변화 및 조간대 해빈 특성을 조사하기 위하여 1년 동안 지형, 표층퇴적물, 퇴적율과 해안절벽의 침식율 등을 조사하였다. 천수만의 해안선은 심하게 풍화된 퇴적암과 풍화토층으로 구성되어 있고 관측결과 -58.9~-73.3 cm/yr 후퇴하였다. 해안침식을 지시하는 톱날 모양의 해안선, 고조선 해빈의 전석, 침식되지 못하고 남아있는 잔류암맥, 그리고 바위섬 모양의 "Island Stack" 등의 여러 가지 특징들이 발견되었다. 한편, 해빈 퇴적물의 조성 성숙도는 돌출부에서 만입된 중앙으로 갈수록 성숙된 경향을 보인다. 이는 해빈을 구성하는 사질퇴적물의 기원이 남측과 북측의 돌출부에 있음을 의미하며, 침식된 퇴적물은 파랑에 의해 야기된 연안류에 의해 만입된 중앙으로 이동되는 것으로 해석된다.

Rapid industrialization has brought Nam-Hae area serious environmental problems associated with released oil and other hydrocarbons. In this work, in order to enhance the quality of the shoreline sediment we made enviro-chemical analyses of its substances, TPHs and microbial growth after treating with oxygen releasing compound(ORC) such as MgO2. Total organic compound(TOC) was reduced from 33.45% to 25.1∼31.08% meanwhile COD decreased from 27.5∼28.9mg/g·dry to 19.9∼26.1mg/g·dry for input of 2∼10% MgO2 in 20days. For 10% MgO2 input, TP and TN were reduced by 13.3% and 18.8%, respectively. Most of all TPH was decomposed by max. 42.4% in 21days, and the total viable count of microbes was found to be exponentially increased by 75.9%.

A numerical model for practical use based on the 1-line theory is presented to simulate shoreline changes due to construction of offshore structures. The shoreline change model calculates the longshore sediment transport rate using breaking waves. Before the shoreline change model execution, a wave model, adopting the modified Boussinesq equation including the breaking parameters and bottom friction term, was used to provide the longshore distribution of the breaking waves. The contents of present model are outlined first. Then to examine the characteristics of this model, the effects of the parameters contained in this model are clarified through the calculations of shoreline changes for simple cases. Finally, as the guides for practical application of this model, several comments are made on the parameters used in the model, such as transport parameter, average beach slope, breaking height variation alongshore, depth of closure, etc. with the presentation of typical examples of 3-dimensional movable bed experimental results for application of this model. Here, beach change behind the offshore structures is represented by the movement of the shoreline position. Analysis gives that the transport parameters should be taken as site specific parameters in terms of time scale for the shoreline change and adjusted to achieve the best agreement between the calculated and the observed near the structures.