皇甫川流域产流产沙数学模型及水沙变化原因分析

Study on Mathematical Model of Runoff Sediment Yield and Analysis on Reasons for Changes of Runoff and Sediment Yields in Huangfuchuan Watershed

该模型是从泥沙运动力学的基本理论出发，结合水文学、气象学、土壤学和地理地貌学的原理建立起来的。并着重解决了在大流域计算中流域的地理、地貌的差异性和降雨在时空分布上的不均匀性问题。利用前人采用的遥感技术资料和实地调查资料，将皇甫川流域分为三大流域、１４个小流域、５１０个计算小单元。在径流系数的选取上考虑了前期降雨的影响。经过对１９６６年至１９６９年５９组９４４场降雨、径流和输沙资料的验证，计算精度良好。应用该模型对皇甫川流域１９７０年至１９８９年次暴雨产流产沙进行了计算，分析了皇甫川流域水沙变化原因。结果表明数学模型的计算成果基本合理。

A mathematical model, based on the theory of sediment transport combining with the principles of hydrology, meteorology, geomorphology and the characteristics of sediment in the Middle Yellow River, has been established. The thesis emphatically solved the geomorphologic and geographical differences, and the differentiated distribution of precipitation in terms of time and space in the watershed. To formulate this model, Huangfuchuan basin is divided into 3 small watersheds and 14 subwatersheds including 510 small areas with different geomorphologic properties by using the remote sensing technology and analyzing the data of the on the spot investigation. The precipitation in early days was taken into account when selected the runoff coefficients. The results of runoff and sediment yields calculated by this model for single rainstorm agree quite well with the measured data. The sediment yield of the gullies from each small area are calculated by using the model according to its specific conditions. The reasons of the changes of runoff and sediment yields were also analysed. It was shown that the calculated results of this mathematical model is reasonable. Therefore, the model can predict the changes of the runoff and sediment yields if the processes of precipitation are known, and can be spreaded to the calculations of the runoff and sediment yields in single rainstorm in loess region of the Middle Yellow River.