Author(s): Luo Qiang; Nobuyuki Tamai; Yangwen Jia; Guangwei Huang
Keywords: GIS; Image processing; Water resources; Watershed; Stream network
Abstract: For river basins in plain and urban areas, the GIS generated stream networks and watersheds are insufficient and partly incorrect. Rectification and correction in these areas are necessary by the aids of introduction of data other than DEM data and other software in addition to GIS. CSWM makes use of topographic maps and a sketch map of watersheds as other kind of data source, and Photo Shop as another software tool. The model has two parts. In the first part, CSWM generates stream networks by GIS with DEM data, then extracts stream networks from the image of topographic maps. After that, the two networks are matched with each other and rectified with each other. Finally, an image of stream networks is generated and a digital file is output. In the second part, CSWM scans a sketch map of watershed boundaries, overlays the stream networks to them, revises the sketch watersheds. Then, CSWM generates watersheds by GIS, overlays it and the stream networks to the revised sketch watersheds, and modifies the watersheds to produce the final watershed image. Finally, outputs a digital data files of watersheds. The model is validated by applying to Kanto region of Japan. CSWM provides an effective support system for runoff analysis on water balance analysis in large areas.