Theoretical and Empirical Analyses on the Possibility of Water Quality Trading

本研究旨在探讨水质交易（WQT）作为一项实用的水质保护政策的可行性。我们从理论上和经验上考察了两个WQT系统的福利属性，即Hung和Shaw （JEEM, 2005）提出的交易比率系统（TRS）和Farrow等人（Land, 2005）提出的以损害计价的交易比率系统（DTRS）。我们的主要发现是：(1)在河流系统的现实条件下，TRS倾向于排除福利改善的交易，而DTRS倾向于鼓励福利减少的交易；(2)它们的相对效率取决于河流流域污染源的地理分布；(3)尽管如此，未能获得许可的总供应量比未能获得许可的空间价格造成的效率损失更大。此外，我们确定了明尼苏达河流域磷污染的总最大日负荷（TMDL）法规及其相关的WQT政策作为我们实证研究的研究领域。我们估计了在TMDL法规下44家水处理厂除磷的（边际）减排成本。该项目目前正处于利用估计的减排成本实施我们的实证模拟工作的阶段。

This research project investigated the viability of water quality trading (WQT) as a practical water quality conservation policy. We examined, theoretically and empirically, the welfare properties of the two WQT systems, the trading ratio system (TRS), proposed by Hung and Shaw (JEEM, 2005), and the damage-denominated trading ratio system (DTRS), proposed by Farrow et al.(Land, 2005). Our main findings were(i) TRS tends to preclude welfare-improving trades whereas DTRS tends to encourage welfare-decreasing trades under realistic conditions of river systems(ii) their relative efficiency depends on the geographic distribution of polluting sources in the river basin, and(iii) nonetheless, the efficiency loss due to failing to get the total supply of permits is larger than that due to failing to get the spatial prices of permits. Furthermore, we identified the total maximum daily load (TMDL) regulation and its associated WQT policy for phosphorus pollution in the Minnesota River basin as a study area for our empirical research. We estimated the (marginal) abatement costs of phosphorus removal at 44 water treatment plants under the TMDL regulation. The project is currently at the stage of implementing our empirical simulation work using the estimated abatement costs.