Soil Erosion and Sediment-Yield Prediction at Basin Scale in Upstream Watershed of Miyun Reservoir: Fid-Bau Portal

Soil Erosion and Sediment-Yield Prediction at Basin Scale in Upstream Watershed of Miyun Reservoir

Li, Xiaosong / Wang, Hao / Zhang, Lei / Wu, Bingfang

Appropriate methodologies for predicting erosion and sediment yield at the basin scale are of utmost importance for taking proper measures to reduce reservoir sedimentation and protect water resources. In this study, a new site-specific distributed and objective model, which was designed based on the spatially distributed scoring model (SPADS), was developed for the upstream watershed of the Miyun Reservoir (UWMR) in China. The model describes the relationships between watershed characteristics and sediment yields. The results show that vegetation, lithology, and inverse distance to the river were the main controlling factors of the specific sediment yield variation in the UWMR. On the basis of these results, a site-specific erosion and sediment yield index (ESYI) was established for erosion and sediment yield predictions at the basin scale. The ESYI-based sediment yield prediction accuracy ( $R^{2} = 0.62$ , relative root $mean square error = 44.7 %$ ) was found to be significantly lower than that from SPADS. However, because the proposed model is advantageous in terms of its low data requirements, and because it takes into consideration spatially distributed characteristics, comprehensive erosion types (sheet, rill, gully, and bank), and both on-site and off-site erosion effects, it may still be of great use in the UWMR.