CHANGES IN ECO-ENVIRONMENT AND CAUSES FOR LAKE TAIHU, CHINA
太湖生态环境演化及其原因分析

Lake Taihu located in the Changjiang River Delta, has been characterized by its shallowness with a water surface area of 2 338km 2 and a mean depth of 1.9m. Its flat topographic catchment made the complexity of hydraulic connection between the rivers and the lake. The major runoff comes from mountainous west and southwest of watershed of Lake Taihu, and flows out throughout East Taihu Bay and the River Wangyu in northeast which flush into Huangpu River and Changjiang River. This causes shorter water retention in the south of lake than that in the north. In the past decades, eutrophication problem gradually became serious with a large amount of pollutants from Wuxi City and Changzhou City discharged into Wuli Bay and Mailiang Bay in the north of Lake Taihu. The water quality, therefore, is much worse in the north than that in the south of the lake. Aquaculture in East Taihu led to water quality deterioration and eutrophication, which caused the problem of water supply in the surrounding areas. In addition, the function of East Taihu for flood discharge resulted in the increase in sedimentation rate and made this area toward marsh. Reclaimation around the lake due to development of agriculture production and construction of water conservancy facilities over the rivers resulted in the reduction of pollutant retention ability. Solutions for these problems need an enhanced management based on the understanding of the changes in the lake eco system.