Kim, D.-H.; Ryu, H.-R.; Yang, S.-H., and Hwang, K.-N., 2021. Measurement of erosional parameters using ASERA, Automated Sediment Erosion Rate Apparatus. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 111 –115. Coconut Creek (Florida), ISSN 0749-0208.
The stability of tidal flats along the west coast of Korea is a matter of national interest due to their significant role as a protector of the shoreline against erosion by storm surge and waves. Depending on the locations of these flats, their materials range from gravel to clay and their stabilities against currents and waves are highly sensitive to material properties. Stability parameters of immediate interest are the critical shear stress and the sediment load for coarse particles and the shear strength against erosion as well as erosion flux for cohesive sediment. Since in situ determination of these parameters is cumbersome during storm events, it is customary to collect cores of the top layer and analyze them in the laboratory under simulated severe flows. To that end, in recent years the Automated Sediment Erosion Rate Apparatus (ASERA) has been developed. The apparatus consists of a rectangular duct through which water erodes the surface of the bed extruded from a practically undisturbed core at a controlled rate. Also, it is equipped with a laser system along with a high-quality CCD camera for accuracy and consistency in the detection and tracking of the eroding bed. In this study, the ASERA has been evaluated on a preliminary basis through a series of tests to verify its effectiveness with coarse and cohesive sediments. Fifteen coarse sediments ranging from very-fine gravel to very-fine sand were used to determine the critical shear stress and the sediment load. For cohesive sediment the bed shear strength and the erosion flux of uniform density bed of commercial clays were measured. The results for both types of sediment yielded values consistent with the available data and formulas, and it indicates that ASERA has a promising potential for the characterizing mudflat sediments.