Simulation Study Of Hydrological Processes In The Qinshui River Basin

Watershed models have become essential and effective tools to the simulation of hydrological processes and watershed management in recent years. They have been applied to investigate the mechanism of water movement between surface and subsurface, and to reveal the watershed response to altered scenarios for future water resource management. HSPF is a comprehensive, conceptual, dynamic watershed scale model which is designed for application to most watersheds using existing meteorological and hydrologic data.In this research, the Guishui River basin located in the northwest of Beijing was selected as the study area. Establishing the spatio-temporal database was the first and essential step of running the hydrologic model, which was based on the GIS and RS techniques. And the selection of the right data source for the extraction of watershed characteristics play an important role in hydrologic simulation process, the difference in hydrological information extraction between Aster GDEM and DEM generated by contour was discussed in this paper.After the establishment of database, the HSPF model was generated, the huge number of parameters were then been calibrated based on the researches of others in similar study areas, and the data come from Water Authority of Yanqing county. The HSPF model was finally established by calibrating against the observed streamflow data from Dongdaqiao gauging station on Guishui River. The goodness of fit coefficient and volume difference were selected to verification the difference between simulation result and observed data.Then the spatial-temporal land use change in past three decade years was analyzed using GIS spatial analysis tools, The various types of land use changes in the region as well as spatial changes of major types of land use, their distribution characteristics and regional orientation are revealed. By the application of Scenario simulation method, the response of land use change to hydrological processes in Guishui River basin was concluded. The results showed that the R2and Dv in the calibration period of the years2007-2008were0.86and14.52%, respectively; the results of validation years2005-2006were0.68and16.24%, which revealed that the HSPF model was suitable for longtime dataset hydrological processes simulation researches in Guishui River basin. The land use change analysis between1980-2005year shows that the "Irrigated crop" turned to "Urban or Built-up La" play an important role with the importance degree of85.22%, and the land use changes from "Agricultural land " to "Urban or Built-up La";"Irrigated crop","Agricultural land ","Range land " to "Forest land" and "Range land " to "Irrigated crop" are the less important changed types by the importance degree between20%-10%. From the hydrologic response to land use change analysis we can see that with the land use type of1980year, the simulation result of HSPF model was less than the result generated by the land use of2005year, and the dominate factor was the land use change from "Irrigated crop" to "Urban or Built-up La"...