Health evaluation of Dongting Lake based on morphological characters
基于形态结构特征的洞庭湖湖泊健康评价

The lake's morphological characters is closely related to the functions of lake ecosystem. It is fundamental to evaluate service function and healthy conditions. According to historical literatures, maps, water and sediment data from 1986 to 2010, 8 indicators of morphological characters including the exposed frequency of bottomland, hydrodynamic conditions and geometry form of the lake were selected to evaluate the healthy condition of the lake ecosystem during the typical years by catastrophe progression method. It showed that: (1) The East Dongting Lake has a relatively good health status (the average membership grade was 0.7486), but with great fluctuations (0.6775-0.7965); then followed by South Dongting Lake, (0.7311); the West Dongting Lake (0.7269) was the worst one with a minimum fluctuation of health relative membership degree (0.7026-0.7487);(2) In the last 20 years, the health standard of Dongting Lake Basin had showed a tendency of " worse at the beginning then improved". It had the lowest healthy membership grade in 1998(0.6912), and the highest value was in 2004(0.7711), the values of the other typical years were in the middle, which might be the result of the strong support from both the implementation of "4350" project and Three Gorges dam.