黄土丘陵沟壑区沟道的水沙运动模拟

Sediment transport simulation for the drainage network in the gullied rolling loess region

黄土高原支离破碎,沟壑纵横,是黄河流域的主要泥沙源区。为模拟与预测全流域的水沙运动过程,需要建立流域水沙运动模拟模型。为使模型的建立符合实际的物理图景,将流域分为坡面与沟道两大系统,在坡面上建立产流与侵蚀产沙模型,在沟道系统内建立水沙运动模型。根据沟道无实测断面资料的实际情况,本文改进了以扩散波方法为基础的水流演进模型,并在此基础上应用不平衡输沙理论计算泥沙输移,提供了黄土丘陵沟壑区沟道系统水沙运动模拟的一种模式。对于沟道水流挟沙力的计算,验证对比了常用于黄河干流的张红武公式和专为泥沙源区建立的费祥俊公式。最后,作为例子给出了方法在小流域中的应用。

The Loess Plateau is so fragmented and full with channels. It is also the main sediment source region of the Yellow River. As a result, water and sediment simulation models need to be built to simulate and predict the hydrological and sediment processes of the whole drainage area. To make the models match the actual physical processes, the drainage area was distinguished into two systems that are slopes and channels. In this paper, a hyperconcentrated flow routing model is proposed to integrate the runoff and sediment yield model for hillslopes and the gravitational erosion model for gully regions. According to the fact of lacks of measured cross-section shapes, the paper achieved a discharge routing method by improving the diffusive wave method. Nonequilibrium sediment transport theory was applied to simulate sediment transport in channels. Zhang＇s and Fei＇s equations are used to calculate the sediment transport capacity. At last, a simulation example in a small catchment was illustrated.