流域社会经济的水环境效应评估新方法及在南四湖的应用

针对我国湖泊生态安全评估及“一湖一策”工作的需要,初步提出一种流域社会经济的水环境效应评估新方法,与以往思路不同的是,新方法体现了正向作用和逆向反馈、现状水平和未来演变趋势相结合的认知框架,并系统阐述了指标优选、评估标准确定、等级划分和不确定性评估方法.最后,选择水质良好的湖泊代表——南四湖开展案例解析.结果表明:通过当前水平和未来变化速率更能全面认识评估结果,也有利于确定流域社会经济系统调控战略的必要性及潜力、方向和阈值；南四湖评估指数从2000年的“Ⅳ级:较严重”提升到2010年的“Ⅱ级:较轻”,尤其是在2003年和2007年存在2个“跳跃式”提升,但若维持现状规模和高速发展速度,未来20年很可能呈现逐渐缓慢下降趋势,并长期处于“Ⅲ级:一般”水平；为了确保维持现状等级且稳中小幅度上升的趋势,到2030年,建议南四湖流域社会经济发展速度控制在过去11年平均增长速度的75％左右以下,环境响应措施力度可能需要提升到评估标准的Ⅰ级水平.

New approach to assess the aquatic effects of watershed socio-economic development and its application in Lake Nansihu

To support China's lake assessment and identify potential solutions, a new approach is proposed to assess the aquatic effects of watershed socio-economic development. Different from traditional works, the conceptual framework of the proposed assessment approach emphasizes the integration of the forward effects and backword feedbacks and of the current conditions and future trends. Indicator selection, assessment criteria, grade level and uncertainty estimation are updated and clarified systematically for the proposed assessment approach. This approach is adopted in Lake Nansihu, one of the lakes in China with good water quality. The results indicate that (i) the conceptual framework is powerful in rapidly identifying the necessity, potential, direction and threshold of watershed-scale socio-economic regulations; (ii) the assessment index for Lake Nansihu was improved from level IV at 2000 to level II at 2010, however, it would decrease slowly in next 20 years and fluctuate around level III in a long run; and (iii) it is suggested to lower the developing rate at 2030 to be about 75% of the average rate in past 11 years so as to maintain the assessment index of level I of the assessment criteria.