Impact of different types of sediment-filled check dam systems on runoff erosion dynamics in a Loess Plateau watershed

Check dams, as one of the most representative soil and water conservation measures in the Loess Plateau region, primarily impact hydrological and hydrodynamic processes by regulating flows of water and sediment. Constrained by reservoir capacity, sediment accumulation within check dam systems affects their ability to intercept water and sediment. However, there has been limited research on the regulatory role of sediment-filled check dams on watershed hydrodynamics. This study focused on small watersheds in loess hilly gully areas and applied the MIKE SHE model to simulate hydrodynamic processes under different scenarios of filled check dam systems. The regulatory effect of different filled check dam system types on watershed hydrodynamics in the study area was analyzed. The results indicate that after sedimentation in various types of check dams, the peak flow can be reduced by 59.68%–68.66%, the flood duration can be extended by 42.74%–375.81%, and the runoff erosion power can be reduced by 62.92%–85.35%. The reduction in flood volume diminishes with increasing sedimentation, reaching a minimum of 2.42%. Moreover, there are varying degrees of reduction in runoff erosion dynamics in the main channels. These findings provide theoretical support for identifying the regulatory potential of sediment-filled check dam systems on hydrodynamic processes in small watersheds.