LI Linlin, LU Shaoyong, MENG Wei, LIU Xiaohui, GUO Xiaochun, WAN Zhengfen
Science & Technology Review. 2017, 35(9): 13-22.
In recent decades, lake eutrophication has severely limited the economic and social sustainable development in the lake basin. To repair the ecological environment and promote the development of the Yangtze river economic belt, solutions to the lake’s eutrophication problem are urgently needed. The six key lakes along the Yangtze river are taken as the research objects, and their historical changes, characteristics, cause analysis and control measures for eutrophication are discussed. It is shown that the eutrophication indexs of the six lakes have been gradually reduced in recent years and the state of lake eutrophication has a tendency of getting better. Causes of lake eutrophication are complex, the main influence factors include exogenous input and endogenous release. In terms of of lake forms and hydrological conditions, the six lakes are shallow lakes and mostly are closed or semi-closed state, which is advantageous to the accumulation of nutrients and algae growth. The control measures of exogenous input are relatively mature and can greatly reduce the nutrients discharged into the lake, such as the expansion of the sewage treatment plant, improvement of sewage treatment and supporting pipe network construction. But for internal release, the governance process is relatively complicated. At present there are mainly physical and chemical methods and technologies such as dredging, sediment oxidation, chemical precipitation, sediment cover, microbial agents, biological floating bed, and so on. Due to the differences of physical and chemical conditions, the applicable method to each lake is also different, so the appropriate lake endogenous control technology remains to be demonstrated. Controlling nutrients input from inside and outside sources, executing river ecological restoration and security governance, and management together could ensure the long-term effectiveness of eutrophic lakes governance.
