GIS-based sediment transport in Asian monsoon region

Steep slope, heavy rainfall and forested cover have unique soil erosion and sediment transport in South Korea. Sediment transport pattern in the monsoon region (from June to September) is complex and sediment transport modeling in these areas is often difficult as sediment load in the river varies largely from year to year. This paper describes a GIS-based soil erosion model and then developed a sediment transport model to estimate sediment yield (SY) at different basin scales. The model for estimating suspended sediment is based on Revised Universal Soil Loss Equation and suspended delivery ratio (SDR) models. For applying SDR model, basin-specific parameter was validated on the basis of field data, which ranged from 0.6 to 1.2 based on observed SY. In the study region, the high flow rates lasted for 4 months (from July to September) and over 90 % of total SY discharged during that time. At that time, it was found that annual bed loads in this area are 56–84 % of total sediment loads.