Analysis of Geo-Environmental System of Dongting Lake

Dongting Lake, the second largest fresh water lake in China, is increasingly shrinking. Dongting Lake geo-environmental system is an organic whole composed of interactive factors of tectonic subsidence, silt deposit and embanked reclamation. Based on analysis of contributions of these three factors to the Dongting Lake evolution and their interrelations, it is concluded that the amount of tectonic subsidence is more than silting amount. The lake area would increase if it were under the natural conditions, and the shrinkage of water area of the Dongting Lake results from reclamation, an irrational human activity. Reconstruction of a new human-natural-compound geo-environmental system coordinately developed is proposed. In addition, influences of the Three Gorge project to the Dongting Lake evolution are evaluated.