The Application Of TOPMODEL In Runoff Simulation Based On GIS

With the development of GIS and remote sensing and computer technology,Distributed Hydrological TOPMODEL are widely used in the development andutilization of water resources, flood prevention and disaster reduction, urban planning,the response of hydrological processes to land-use change, and many other aspects ofa wide range of applications. In this thesis, it achieves the target to simulatecatchments runoff process by combining TOPMODEL and geographic informationsystem (GIS), and it also provides the technical support for the flood forecast forwatershed planning management.The focus of this thesis is to discuss the applications of semi-distributedhydrological model TOPMODEL, supported with GIS, in the catchments runoffsimulation. TOPMODEL is chosen for the study because it has simple structure andfewer numbers of parameters. Based on the data availability, TOPMODEL is adoptedto simulate the Pocono catchments runoff process by combining with GIS analysistools. The main research results are as follows:(1) The basin information has been extracted from DEM by using GIS tools from10 m resolution of catchments digital elevation model (DEM).The information iscomposed of water flow direction, confluence direction, confluence accumulation,confluence length and slope, etc. In this study, it also uses Visual Basic language toimprove the input module of TOPMODEL and realize the model of input file format,which improves the operation efficiency of the model.(2) Based on the analysis and introduction of the structure, the principle and thefundamental equation of TOPMODEL, this thesis explores the TOPMODEL coretopographic index computational method through the comparison among three kind ofcomputational methods: the single flow direction algorithm, and multiple flowdirection algorithm, and improved multiple flow direction algorithm for thetopographic index. In addition, two different methods of sub module calculation andARCGIS10 calculation are also introduced to calculate topographic index. Then, theresults from these two methods are contrasted as well.(3) The paper studies the change of the TOPMODEL simulation accuracy underdifferent scales of DEM and solves the problems of rapid format of input data. Theuncertainty concept of the hydrological model, the principle and analysis method ofGLUE are discussed comprehensively. Using the application of TOPMODEL to thePocono catchments as a case study, this study uses the random generation parametersto run TOPMODEL according to the experience of the prior distribution parametersgiven. Once the parameters are determined, the TOPMODEL is adopted to simulatethe catchments runoff process. The comparison of the results between simulated dataand real data indicate that the deterministic coefficient demonstrates is 86%, and thesimulation results satisfy with accuracy requirement of hydrological simulation,which has verified the rationality of the model.