Simulation Of Runoff And Sediment Discharge Respond To Landuse And Landcover Changes Based On SWAT Model

Landuse and Land-cover Change(LUCC) is a core field of the global change. LUCC not only changes the physical landscape, but also affects the material circulation and energy distribution. As one of the environmental effects of LUCC, how runoff and sediment discharge respond to LUCC become the point of hydrology and ecology hydrology.Loess Plateua, which is imited by the adverse natural environment and the laggard economy, is the most serious region of the soil and water losses in China even in the world. How to recover the ecology and environment of Loess Plateua is one of the most urgent issue. In this dissertation the SWAT (Soil and Water Assessment Tool) model was used to simulate the hydrologic and soil erosion processes. The main findings and contributions of this dissertation include:(1) The Landuse data of 1980 and 2000 is used in this paper to analyze the LUCC of the study area by making use of spatial analyze function of GIS. The LUCC during the period of 1980-2000 put up a sharp decrease of grass and a high increase of urban landuse. Based on the CA-Markov method, this paper calculate the landuse transition probability and transition area of each landuse type, and then forcast the landuse of 2010.(2) Under the support of GIS technology, an input database of SWAT model is constructed, including spatial database and attribution database.In order to discretzate the watershed, a digital stream network is extracted from the DEM and the watershed is subdivide to 47 subbasins and 221 hydrogical response units.(3) The 20 year (1980-2000) data was used to simulate the runoff and sediment discharge. From analyzing the sensitivities of the model parameters gain the most sensitive parameter of the SWAT model. The simulation period is divided into two...