The 24th IAHR-APD Congress (24th IAHR-APD Congress)

364 / 2024-02-29 21:30:57

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

regulating effect; check dams; flooding; runoff erosion rate; sediment transport modulus

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. The results show a power function relationship between the runoff erosion rate and the sediment transport modulus for cases with and without the check dam, but the relationship with no check dam cannot be extended to cases with check dams due to the regulating effect of check dams. The main mechanism of check dam system to reduce sediment transport rate is that the check dam reduces flood peak discharge and runoff erosion rate. The effect of parallel arrangement on flood peak discharge is weak, while the effect of series and hybrid arrangement is strong. With the decrease of flood frequency, the influence of series and hybrid scenarios on sediment transport increases.