Because self-purification ability is decreasing while the water level of the Three Gorges Reservoir is rising to 175 meters,there is a eutrophication trend in Yangtze River branches.In order to prevent water eutrophication,sewage treatment in small towns is necessary.Constructed wetland is an effective,cheap and simple method for sewage treatment and can realize sewage recovery.The constructed wetland in the Three Gorges Reservoir area is construced by taking advantage of the characteristics of the hills an...