Research on mechanism of gully consolidation and check dam efficiency in reducing erosion based on GeoWEPP model in Yangjiagou Watershed

Soil erosion is an crucial problem faced by ecological management in the world today. As a part of “Gully Consolidation and Highland Protection (GCHP)” project, check dam plays an important role. In this study, the applicability of GeoWEPP model in typical small watersheds of the Loess Plateau was evaluated, and the erosion and sediment production of check dams under the time scale scenarios of 10, 20, 50 and 100 years were simulated to study the response of hydraulic erosion to check dam. The results show that the relative error δ between the runoff data generated by GeoWEPP simulation and the measured data is less than 15%, the correlation coefficient γ is greater than 0.994, and the Nash efficiency coefficient NSE is greater than 0.98, indicating that the model has good applicability. And the results show that with the increase of time, the effect of the check dam in controlling soil erosion has declined. Under the condition that other parameters remain unchanged, the sediment yield changes little in the first 10 or even 20 years after the construction of the check dam. After 50 years, sediment yield increased significantly, and the role played by the silt dam was significantly weakened. This study is of great significance for reducing soil erosion and promoting the sustainable development of the Loess Plateau.