Estimation of the sedimentation budget in tidal flat using remotely sensed data

The intertidal topography is continuously changed due to morphodynamic processes. The objectives of this study are: (i) to generate an intertidal digital elevation model (DEM) using waterlines extracted from Landsat TM; (ii) to estimate sediment budget and to analyze sediment pattern using generated DEMs 1991 and 2000. The band ratio of (TM4-TM3)/(TM4+TM3) is shown to be most effective. We tested the proposed method in Gomso Bay, Korea, and successfully produced intertidal DEMs with 10.9 cm rms error. The sediment budget and pattern analysis were quantitatively estimated by differencing the two DEMs. A comparison of DEM1991 with DEM2000 deduced from 13 Landsat TM scenes shows sedimentation dominant in the lower flat and no significant changes in the upper flat. The grain size of the surface sediment may not directly be correlated with reflectivity. The results demonstrate that remote sensing is a useful and valuable tool for the intertidal flat studies, and practically the one and only possible way to provide reliable data of the two-dimensional sediment budget and pattern.