만경강 기수역 하상 세립 퇴적물의 침강속도 산정

An estimation of settling velocity for fine bed sediments from brackish water zone of Mankyung river

The purpose of this study is to quantitatively estimate the settling velocities of fine sediments in the Mankyung brackish water zone and to analyze their spatial changes by comparing with those of sediments from other regions. This study also includes the measurements of salinity of water and physico-chemical properties of sediments, such as grain size distribution, the percentage of organic contents, mineralogical composition, in order to examine their effects on spatial variation of setting velocities. Results from setting tests show that the setting velocities of Mankyung sediments varies in the range of two orders of magnitude (0.017 < Ws < 0.506 mm/s) over the corresponding concentration range of 0.1 to 80 g/L. The settling velocity profile measured for Mankyung sediments is shown typically to have similar features with those for marine (Saemangeum lake, Incheon coast) sediments, while it is quite different with those for river (Han river, Kulpo stream) sediments. These results are interpreted to be due to the presence of salinity in the brackish water zone, rather than physico-chemical properties of sediments.