PRELIMINARY RESULTS ON THE ANALYSIS OF GEOMORPHOLOGIC CHANGE OF THE TIDAL FLAT IN GOMSO BAY BY THE CONSTRUCTION OF SAEMANGEUM DYKE

Abstract

Gomso bay, a funnel-shaped embayment with 7-9 km wide and 20 km long, is located on 15 km south from the Saemangeum dyke which had the enormous reclamation works with 33 km long dyke from 1991 to 2006. Morphological change of tidal flats in Gomso bay were estimated based on the waterline mehod (Ryu et al., 2008) and change of suspended sediment around Gomso bay and Saemangeum area were investigated (Lee, 2010 Min et al, 2012). However, interactions between tidal flats and suspended sediment have not been studied. The purpose of this study was to quantitatively estimate geomorphologic change of the tidal flats in Gomso bay together with hydrodynamic approaches and sediment patterns for understanding the cause-and-effect of deposition and erosion by construction of Saemangeum dyke. The intertidal digital elevation models (DEMs) were generated for 1990, 2000 and 2010. Ground leveling was carried out along the 3 lines (KM, KH and KB line). Water samples for suspended sediment concentration (SS) were collected from 2005 to 2012 not only Gomso bay but also around Saemangeum area.The samples from 2012 included at the fixed points at about every 60 minutes from 9:30 to 16:30 at local time. The erosion was dominant in the outer Gomso bay area, especially at the front of the funnel-shaped area, whereas sedimentation was observed at the inner bay, especially eastern parts of Jujin stream. The chets in Gomso bay were estimated based on the waterline mehod (Ryu et al., 2008) and change of suspended sediment around Gomso bay and Saemangeum area were investigated (Lee, 2010 Min et al, 2012). However, interactions between tidal flats and suspended sediment have not been studied. The purpose of this study was to quantitatively estimate geomorphologic change of the tidal flats in Gomso bay together with hydrodynamic approaches and sediment patterns for understanding the cause-and-effect of deposition and erosion by construction of Saemangeum dyke. The intertidal digital elevation models (DEMs) were generated for 1990, 2000 and 2010. Ground leveling was carried out along the 3 lines (KM, KH and KB line). Water samples for suspended sediment concentration (SS) were collected from 2005 to 2012 not only Gomso bay but also around Saemangeum area.The samples from 2012 included at the fixed points at about every 60 minutes from 9:30 to 16:30 at local time. The erosion was dominant in the outer Gomso bay area, especially at the front of the funnel-shaped area, whereas sedimentation was observed at the inner bay, especially eastern parts of Jujin stream. The che