Impacts of 20-year socio-economic development on aquatic environment of Lake Dianchi Basin

滇池是我国著名的高原淡水湖泊,滇池流域是云南省社会经济发展最为活跃的区域.通过对1988-2009年流域社会经济发展和水环境变化情况进行系统调查,分析流域水环境问题的主要影响因素,并在此基础上进行趋势分析.结果表明,近20年来滇池流域人口数量年均增长3.3%,GDP年均增长18%,城市化率提高了17%;伴随着社会经济的快速发展,流域用水总量及污染物排放总量持续增加,由此导致流域主要河流水体水质恶化趋势明显,Ⅴ类水质河流占比增长了近4倍,滇池草海、外海水体水质恶化为劣Ⅴ类,水体水质恶化及湖泊富营养化已成为滇池面临的重要水环境问题,且短期内难以有大的改变.最后从产业结构优化、污水处理系统建设、污水再生利用、农村环境保护、生态补偿机制等方面探讨了解决目前滇池流域水环境问题的主要措施及建议.;Lake Dianchi is a famous plateau freshwater lake, whose basin is the most active area of socio-economy in Yunnan Province. Through systematic investigation socio-economic development and changes of aquatic environment in 1988-2009, the main influencing factors of such changes were analyzed. Results showed that the annual increasing rate of population, GDP, and urbanization in the Lake Dianchi Basin reached 3.3%, 18%, 17% in recent 20 years, respectively; With the rapid development in socioeconomy, total water consumptions and pollutant emissions continuously increased. At the same time, the water quality in main rivers deteriorated significantly, with the percentage of rivers with water quality type-Ⅴ increased by nearly 4 times. The water quality of inner (Lake Caohai) and outside of the lake were degraded to worse than type-Ⅴ. The deterioration of water quality and lake eutrophication have become important water environmental problems in Lake Dianchi, which are difficult to be relieved in the short term. In the basis, we proposed some measures and recommendations to improve the water environment in the basin, including optimizing industrial structures, construction of sewage treatment systems, wastewater reclamation, rural environmental protection, ecological compensation mechanism and so on.