DEM and ArcGIS-Based Extraction of Eco-Hydrological Characteristics in Ya´an, China

This paper, on the basic principles of extraction of hydrological information by DEM (Digital Elevation Model), applies the toolkit in ArcGIS 9.0 for the analysis of the hydrological information, extracts eco-hydrological characteristics of stream basins in Ya´an. Information such as flow direction, flow accumulation, flow length, stream networks, and snap pour point are obtained. The spatial distribution of stream networks, with catchment area threshold beyond 9900, has the maximum similarity with the actual river system. ArcGIS 9.0 thematic maps and comprehensive evaluation could be done about single factor and combined factors of health risk caused by carcinogens and non-carcinogens in rural drinking water quality of the seven counties and one district in Ya´an City, so as to provide scientific basis for water governance and data support for further research of ecohydrology in Ya´an.