Modeling the impacts of fully-filled check dams on flood processes using CAESAR-lisflood model in the Shejiagou catchment of the Loess Plateau, China

Study region: The Shejiagou catchment on the Loess Plateau, China Study focus: This study used CAESAR-lisflood to simulate the impacts on flood processes of fully -filled check dams with different numbers, silt land areas and connection modes. According to the model results, the protective measures of fully-filled check dams and recommendations for pro-moting the construction of check dams were proposed in the study.New hydrological insights for the region: CAESAR-lisflood model in the study obtained higher ac-curacy with both the Nash-Sutcliff coefficient of efficiency and the coefficient of determination greater than 0.8. Our results showed the presence of fully-filled check dams made the flood process tend to balance, and reduced the flood volume by 9.56-75.52%, peak discharge by 14.25-89.74%, runoff kinetic energy by 30.21-99.75% and runoff power by 20.17-95.23% under different layout scenarios. Meanwhile, the results indicated that the impacts of fully-filled check dams in main channel mainly manifested in the energy dissipation of silt land and energy increase at the outside slope of dam body, which was aggravated by downstream channel with steep slope. The combination of fully-filled check dams could amplify the flood control efficiency of individual dam. These results provide a scientific basis for reinforcement of fully-filled check dams and optimization of check dams layout in the future on the Chinese Loess Plateau.