Research Of Runoff Simulation In Qingzhang Basin Based On SWAT Model

Distributed hydrological model in a region considers differences of varioushydrologic elements in space, so as to the result of the simulation of rainfall runoff iscloser to the fact. Thus it improves the precision of hydrological simulation. This papersimulates the formation process of rainfall runoff in the upstream of the Zhang Riverthrough the analysis of hydrological model, and then it provides a scientific basis for theunity management of the upstream of the Zhang River.This paper chooses the Liu Jiazhuang hydrological station as watershed entry, andresearches the rainfall runoff for the drainage area controlled by the station. Thecontents and results are as follows:First of all, on the basis of summarizing the research achievements of predecessors,this paper introduces the theoretical basis, research methods and the development trendof the distributed hydrological model and expounds the application of geographicinformation system in extraction of hydrological parameters and the calculation ofhydrological process. Through collecting a large number of relevant literature and data,this paper uses ArcGIS9.3software to make some analysis about the digital elevationmodel. Through the analysis and comparison, this paper chooses the SWAT (Soil andWater Assessment Tool) model developed by American Agriculture Department as thebasic hydrological model of the study.Secondly, through reviewing the literature, the map format and transformingcoordinate, calculating parameters related to model, etc., this paper builds up the modelof relational database. And then through the extraction of river network by DEM, thedivision of sub basin, the extraction of the river boundary, the calculation of flow length,the writing of model data, the input of model parameters, the calibration of modelparameters and so on, it establishes the SWAT model of the research region.Finally, through the simulation of monthly runoff of the region in1981-2009, andthe comparison of computation of model and the measured data, this paper makes thefurther revision. Then it discusses the relationship of the rainfall runoff of theresearched region above the Zhang River and the applicability of this model in thisregion. Results show that the SWAT model is suitable to the researched region in the LiuJiazhang hydrological station and that the results of the model are preferable. But at thesame time, in a few special wet years, there is a lager deviation on the simulation results.