Regulating effect of check dams on erosion dynamics and sediment transport during flooding

The regulating effect of check dams on the sediment transport in a watershed is important for improving soil and water conservation and watershed management. Up to now, the studies about the regulating effect of check dam on the flow and sediment movement is mostly focused on an annual scale, and there are few reports on their effect during the rainstorm flood process. Besides that, most researchers use statistical methods to explore the regulating effect of check dams on flow and sediment transport, and the discussion of their regulating mechanisms is lacking. In this study, the effect of check dams during flooding is studied by using a one-dimensional non equilibrium sediment transport model for a small watershed. Three different distribution of check dam system are set up, including series, parallel and hybrid. After the construction of the dam, the flood peak flow rate and flood volume are reduced, and the runoff erosion power is reduced, resulting in a decrease in the sediment transport modulus. With the increase of flood frequency, the regulation effect of check dams on runoff erosion power and sediment transport modulus is weakened, indicating that the regulation effect of check dams on large floods is greater than that on small floods.