Simulation Study, Based On The Surface Hydrology Of Large And Medium-sized Basins Of The Srtm Dem

With the rapid development of digital technology, "3S" technology, digital elevation models (DEM) and Internet technology provide mass information for watershed management. While in the topographic maps digitalization, spatial data management, spatial analysis, digital terrain model building, etc., GIS has provided a powerful development and application platform for digital watershed study. Combination of hydrological and 3S technology is an inevitable trend of development for hydrological model study. Currently data used in hydrological simulation studying, which base on spatial analysis, mostly from digital elevation model. The basin surface hydrological simulation based on GIS and DEM can provide underlying data input for distributed hydrological model.This paper analyzes red river and the Dianchi Lake Basin. Analysis tool is Arc Hydro Tools from ArcGIS. Based on the SRTM DEM, based on the D8 algorithm, we determine grid cell's flow of water flows by the principle of the most steep-degree principle, and river channel and its starting point by catchment area threshold. Also we determine the entire basin and the sub-basin boundaries from the export of sub-basins along the river channel to river upstream search Water District, thereby generating digital Red River and digital Dianchi Lake basin, getting surface model of Dianchi Lake and the Red River basin. Then we analyze river network and watershed extraction accuracy of simulation results.Main research content is as follows:(1) Combining GIS and hydrological models, introducing the watershed feature extraction methods based on DEM, and construct the Red River and Dianchi Lake basin, results showed that river basin network consist with digital River's network of waterways map.Extraction of drainage area and hydrological services in the basic line with relevant data,it can serve as a distributed hydrological model parameters. The same time it can guarantee the accuracy of information extraction. It is also demonstrated that extracting watershed information based on the Arc Hydro Tools, regardless of efficiency or the accuracy are feasible and intuitive.(2) Fitting digital stream into the DEM can increase extraction accuracy of river network, a certain extent, solve the problem that.difference between digital and actual river network in hilly and plain areas. It also increased extraction accuracy of river network in depressions and river plain area;(3) Through watershed extraction experiments of the Dianchi Lake and the Red River basin, which has different scales and forms, shows the advantages of SRTM DEM data used in the large area of surface hydrological modeling.(4) The use of'delineation extract' command in Arc Hydro Tools, we can extract sub-basins at any point. It greatly facilitates the extraction of the sub-basins, thereby lay a good foundation for next work that integrated watershed geology, hydrology, climate, soil, vegetation and other information to establish hydrological model.(5) Introduces a new and effective data source CGIAR-CSI SRTM DEM data, solved the data acquisition problems in some areas.