Determining the Sediment Delivery Ratio Using the Sediment-Rating Curve and a Geographic Information System–Embedded Soil Erosion Model on a Basin Scale

This study presents a model-based approach for determining the sediment delivery ratio (SDR) on a basin scale in Southern Korea. The study builds a sediment-rating curve using the measured suspended sediment concentration and water discharge. The sediment-rating curve is then used to determine the sediment yield. A geographic information system-embedded empirical model is used to estimate soil erosion. The ratio between the sediment yield and soil erosion is used to compute the SDR. The data spanning the year 2002–2008 are divided into two sets. The first set (2002–2005) is used for calibrating the model and the second set (2006–2008) is used for validating the model. For the soil erosion model, the rainfall-runoff erosivity factor was analyzed separately using the rainfall amount and rainfall intensity. The results show that the rainfall-runoff erosivity factor derived from rainfall intensity gives better performance in calculation of soil erosion than does the rainfall amount. The accuracy of these results may vary, depending on model selection and measurement accuracy, but the method used herein should work anywhere.