퇴적작용 제어를 위한 중소형 시설물 현장실험

Abstract

Although the dimension and layout of coastal artificial structures are optimized in many- sided viewpoints, the subsequent changes in the hydrodynamics and sedimentary processes may cause environmentally undesirable problems. In fact, for the past 30 years, due to the various development of large dimension, Korean coastal area has suffered from many environmental problems such as the destruction and reduction of tidal flat, retreat of coastline, siltation of navigation channels, etc. Thus effective policy and methods for sustainable and eco-friendly coastal management have been demanded since early 1990s. Relatively small-scaled low-crest facilities of eco-friendly materials may meet the demands. Three kinds of low-crested facilities, artificial seaweeds, timber fence and gabion groin, were constructed and their effects have being monitored. Artificial seaweeds were installed on Iwon tidal flat of Taean-gun in 2001 and Ganghwa tidal flat in 2004. A timber fence and gabion groin were constructed on Iwon tidal flat and Baeksajang beach of Anmyeondo, respectively.Tidal flats around the artificial seaweeds and timber fence at Iwon have shown seasonal characteristics. During winter season, erosion and coarsening occur due to high waves and wind-driven current, while deposition and fining during mild seasons. It indicates that enhancement of turbulent intensity due to the facilities plays a deposition-promoting role in mild season, while a erosion-promoting role. The low-crested gabion groin to trap the bed load have shown good performance. Judging from the data from various instruments, wind-driven currents cause relatively large transport of sediments.These field applications have shown that low-crested eco-friendly facilities can be effectively and economically used for coastal management. For their good performance, however, the dimension and layout should be properly decided based on the intensive field measurements of hydrodynamics, wind field as well