Abstract: This study proposes a computational method for estimating sediment deposition in check dam systems during individual rainstorm flood events.The method employs a distributed hydrologic-hydrodynamic model to simulate basin-scale rainfall-runoff processes,utilizes runoff erosion power theory to quantify surface flow erosive capacity,and constructs dynamic sediment transport equations incorporating sediment transport modulus.Based on hydraulic principles,a regulation model for check dam drainage structures is established to characterize the cascade regulation effects on water-sediment processes through comprehensive consideration of geometric parameters and operational thresholds.Validation using the “7.26” extreme rainfall event in the Wangmaogou check dam system demonstrated reliable results,with both coefficient of determination and Nash-Sutcliffe efficiency coefficient exceeding 0.6 between calculated and measured sediment volumes across all check dams.This methodology innovatively achieves whole-process dynamical analysis from slope erosion to gully sediment transport in dammed watersheds,featuring explicit physical mechanisms,no basin characteristic constraints,and broad applicability with significant potential for engineering popularization.