水源地生态补偿标准估算——以贵阳鱼洞峡水库为例

鱼洞河是乌江水系的一个小支流,为下游贵阳市提供饮用水水源。在鱼洞河上下游之间建立生态补偿机制,理论上需要知道上游治理污染和维护生态环境的费用,以及下游对上游提供的生态环境服务的支付意愿。只有下游的支付意愿大于上游的费用,上下游之间的生态补偿机制才有理论可能性。在对上游龙里县汇水区进行实地调研后,重点评估了当地安装沼气系统、坡耕地(≥25°)退耕还林、其他地区的土壤侵蚀防治以及点源污染治理费用,得出上游治理投资费用为199万元,年度费用每年89.2万元-168万元。采用意愿调查法(CVM)对贵阳市自来水用户对上游环境服务的支付意愿进行了评估。采用简单随机抽样方法在贵阳3个区内选取了900户作为样本,结果表明,有62.7%的人愿意为生态补偿付费。采用PROBIT模型,可以计算出为避免鱼洞河水质恶化的支付意愿均值为0.37元/m3,贵阳市自来水用户总的支付意愿每年达847万元。结果表明在鱼洞河水源地进行上下游生态补偿理论上是可能的,补偿标准介于上游费用与下游支付意愿之间。

Estimation of Eco-compensation Rate for Headwater Area: A Case Study of Yudongxia Reservoir in Guiyang City

Yudong River is a small branch of Wu River in Yangtze River Basin.It provides drinking water for downstream Guiyang City.In order to establish an eco-compensation mechanism between upstream and downstream in Yudong River,valuation should be done on the costs of pollution mitigation and/or maintenance of the good environment in the upstream on the one hand,and the willingness to pay(WTP) for the upstream environment services by the downstream on the other hand.An eco-compensation mechanism is possible only when the upstream costs are less than the downstream WTP.After investigating catchment area in upstream Longli County,valuation focuses on the cost of constructing biogas system,converting sloping farmland to forest land(more than 25°of slope),preventing soil erosion and controlling point source pollution.The result shows that pollution mitigation needs investment costs of 1 990 000 Yuan(RMB) annual costs of 890 000-1 680 000 Yuan(RMB).This study valuates the WTP for environmental services of water users in Guiyang City with contingent valuation method(CVM).With simple random sampling method,900 households were selected as samples from 3 districts in Guiyang City.The result shows that 62.7% of all respondents were willing to pay for the eco-compensation mechanism.With PROBIT simulation,the average WTP was calculated,which is 0.37 Yuan(RMB)/m3 of tap water,and the household water users in Guiyang were willing to pay 8 470 000 Yuan(RMB) per year in total.Therefore,it is possible to establish an eco-compensation mechanism,and compensation rate is between upstream cost and the downstream WTP.