为精准模拟一维水动力学过程，基于明渠非恒定流的水动力模型，提出耦合改进考斯加科夫（Kostiakov）公式，考虑实际河道渗漏损失动态变化。在同一时间步长上，将水动力模型计算流量作为损失模型流量边界条件，通过损失经验参数a和b计算得出此时间步长河道损失量，对水动力河道损失参数进行实时修正。以永定河流域2022—2024年4场实测补水数据对模型精度进行检验，分析海河“23?7”流域性特大洪水（简称“23?7”洪水）前后永定河河道生态变化特点。结果表明：该模型在永定河流域具有良好适用性，相对误差的绝对值最小为0.004，最大为0.218；“23?7”洪水对永定河河道冲刷作用明显，河道形状发生明显改变，河道糙率与河道下渗损失较洪水冲刷前均减小，永定河下游流域较洪水冲刷前以小流量补水即可实现全流域通水，可为永定河下游生态调水提供参考。

In order to accurately simulate the one-dimensional hydrodynamic process, a coupled improved Kostiakov formula is proposed based on the hydrodynamic model of open channel unsteady flow. Considering that the river leakage loss is affected by the river flow and the underlying surface conditions of the river, the real flow change process under the river is simulated. By coupling the loss model and the hydrodynamic model considering the actual river water loss, the calculated flow of the hydrodynamic model is used as the flow boundary condition of the loss model at the same time step. The loss of the time step is calculated by the loss empirical parameters a and b, and the hydrodynamic river loss parameters are corrected in real time. The accuracy of the model was tested by four measured water replenishment data from 2022 to 2024 in the Yongding River basin, and the characteristics of ecological changes in the Yongding River before and after the "23·7" flood were analyzed. The model has good simulation accuracy in the lower reaches of the Yongding River, and has good applicability in different seasons and different basins. The minimum absolute value of the relative error is 0.004, and the maximum is 0.218, which is within the allowable range of error. The "23·7" flood has obvious scouring effect on the Yongding River channel, and the shape of the river channel has changed significantly. The roughness of the river channel and the infiltration loss of the river channel are reduced compared with those before the flood scouring. The lower reaches of the Yongding River can realize the water supply of the whole basin with small flow before the flood scouring, which can provide a reference for the ecological water transfer in the lower reaches of the Yongding River.