流域非点源污染控制管理措施的成本效益评价与优选

Optimization and economic evaluation on cost-benefit of Best Management Practices in nonpoint source pollution control

最佳管理措施是针对非点源污染的控制方案,相关措施的效果评价和经济效益分析,是进行政策手段设计和有效性评价的主要依据。针对北京市密云水库上游太师屯镇的农业非点源污染特征,设计了多种不同最佳管理措施(BMPs)。在对非点源污染控制措施控制效果的经济价值估算基础上,综合考察各项措施的费用—效益关系,对所选择措施的投入—产出中的各种经济因素进行研究,通过计算出的不同控制措施的费用效益比、内部收益率、投资回收期、经济净现值等经济指标,对各种控制措施进行对比分析,从工程经济的角度分析、评价各种控制措施的合理性,使污染控制方案既满足流域改善环境的目的,又具有经济上的可行性。研究结果表明:污染控制措施在经济上都是合理和接受的。经济优劣排序为:15°～25°坡耕地变果园>河岸植被缓冲带>0°～15°坡耕地保护性耕作>户用沼气池>25°以上荒草坡还林>0°～15°坡耕地等高植物篱;耕地变为果园和河岸植被缓冲带两项措施,非常适合于该地区,前者经济效益显著,后者环境效益显著,值得大力推广。

Best management practices （BMPs） are integrated approaches to prevent non-point source pollution by engineering and management practices. They are widely applied in agricultural nonpoint source pollution controls for their efficiencies, economic and environmental benefits. Policy design and efficiency evaluation refer on cost-benefit analysis of Best Management Practices in nonpoint source pollution control. Taishitun town, locates at upper watershed of Miyun reservoir, Beijing, was selected to evaluate the environmental benefit and economic benefit of several BMPs by using the methodology of environmental economics. Based on the economic value evaluation on effectiveness of Best Management Practices for control of nonpoint source pollution, the cost-benefit relation and various economic factors in input and output of various BMPs have been investigated by calculating the ratio of cost-benefit, internal rate of return, payback period and economic net present value. The results are as follows： All the practices are economic feasible and acceptable with exception of returning farmland to forest, the order of practices by the economic assessment from high to low is： returning farmland to orchard on land with slopes 15°-25°, riparian vegetable buffers, conservational cultivation on land with slopes 0°-15° marsh gas tank for rural household, returning grassland to forest on land with slopes 25° or greater, and returning farmland to contour hedgerow on land with slopes 0°-15°. Especially the practice of farmland to orchard has more economic benefit whereas riparian vegetable buffers has more environmental benefit, both are very suitable for this area and worthy of extension and promotion.