流域泥沙过程模拟中的河道输沙计算

Calculation of Sediment Transport in Channel in the Simulation of Sediment Process in Watershed

全流域的水沙过程包括降雨产流、汇流的全过程,以及泥沙侵蚀、输移、沉积的不同运动形态.对这一物理过程的全面描述有其必要性和现实意义.在数字流域中,将流域水沙过程概化为坡面产流产沙、沟坡区重力侵蚀、沟道水沙运动及河道水沙输运四部分.其中,前三部分的计算能为中下游河道水沙计算提供入口边界条件.本文对前三部分的内容只作简要介绍,重点以一维水动力学模型为工具,以1977年为典型年,完成了流域泥沙过程模拟过程中干流河道输沙计算,并对龙门站的预测水沙过程和实测水沙过程龙门-三门峡河段进行了演算和对比.结果表明,用预测龙门站水沙过程计算中下游河道的水沙演进是可行的.

The whole process of water and sediment in watershed consist of water generation and concentration, sediment erosion, transportation and deposition. It is necessary and meaningful to describe the physical process overall. In Digital Watershed Model, this process is generalized into four parts, water and sediment yield models for hill-slopes, gravitational erosion model for gully ares, and discharge routing and sediment transport model for rill and channel. Moreover, the Simulation results of the former three parts can provide the inflow water and sediment concentration for the forth one. In this paper, after the introduction of the former three parts, it focuses on the forth one. Namely, an one-dimensional hydrodynamic model for sediment is applied here. Then 1977 is selected as a typical year, and forecasted and measured process of inflow and sediment concentration process at Longmen station are computed. Comparison results reveal that, it is available to calculate the flood transport in the middle and lower Yellow River, with the forecasted process at Longment station.