Study On Sediment Yielding Model Of Wangjiashan Reservoir Watershed

The climate of northwest loess region is arid and the water resource is extraordinary deficient. The flood is very frequently and it has a serious loss of soil and water.The large amount of sediment from erosion accumulate in river network and silt seriously, which not only affects the reservoir benefit but also brings problem to environment. It's necessary to do some research on the mechanism of soil erosion and sediment yielding in order to eliminate the soil and water loss of the northwest loess region. The research on slope surface hydrological model, which is the most basic unit of the field, is the basic work to study the slope erosion model. It's the foundation of sediment yielding model to simulate the slope surface runoff yielding and conflux and rainfall-flood process accurately. So it's necessary to research on hydrological and sediment yielding model systematically to forecast flood and reduce erosion effectively.First, the thesis summarizes the production in hillslope runoff and sediment yielding. Then, on fundamental of the transport rule of the soil water in unsaturated zone, working on the infiltration and runoff yielding model combining hydrology with soil-water dynamics, the thesis develops a slope surface runoff yielding model in natural changing rainfall of the northwest uniform loess hillslope basing on others' production. The conventional kinematic-wave method is used to simulate the conflux on slope surface, and the kinematic-wave equation is answered by the finite difference method on the given boundary conditions and discretized by using the first-order explicit upwind scheme.The Zizhou zone of Chabagou in the yellow river basin and the observed hydrological data of No.2 3 4 experimental plot of Tuanshangou between 1963and 1967 are selected as the representative to validate the model. The results indicate that the model can simulate the fact preferably and can be used in the calculation of slope surface hydrological model of northwest loess region.Based on above works, the 8 rainfall-runoff of No.5 experimental plot of Tuanshangou of 1963 and 1967 are simulated by using the model.Basing on the model, adopting the prodecessors' method of sediment yielding calculation, the model is applied to the 《Wangjiashan reservoir sedimentation research of Gansu Jingyuan coal industry CO.LTD》 and the coming streamflow and sediment during the normal operation of the reservoir are forecasted, which provides the basis for the effective operation, and the model is applied to the practice.Finally, the research and production in the thesis are summarized, and the existing problems and the further issues in the future are also presented.