[Zoning of water environment protection in Three Gorges Reservoir watershed]

Regional differences in socio-economic development, land use, vegetation cover, and relative location of water body within a watershed bring about significant effects on the water environment quality of the watershed. Concerning about the core demands of water body protection, it is important and necessary to carry out zoning water environment protection for whole watershed. With a view to the spatial differences in regional characteristics of eco-environment and water body pressure-respond features, this paper studied the zoning of water environment protection in the Three Gorges Reservoir watershed, based on the methods of ecological factors overlay and ecological sensitivity analysis. The factors considered included hydrothermal conditions, terrain topography, administrative unit, and ecological sensitivity. Three regions in the watershed were zoned, i. e., 1) red region, namely strictly protected region, with an area of 2924 km2 and occupying 5.1% of the total; 2) yellow region, namely first class protection region, with an area of 10477 km2 and occupying 18.4%; and 3) blue region, namely second class protection region, with an area of 43599 km2 and occupying 76.5%. The key environmental problems of the regions were identified, and the strategies for the regions' development and water environment protection were proposed.