Ward Frank A, Pulido-Velazquez Manuel
Department of Agricultural Economics and Agricultural Business, New Mexico State University, Las Cruces, NM 88003, USA.
J Environ Manage. 2009 Jan;90(1):293-313. doi: 10.1016/j.jenvman.2007.09.009. Epub 2008 Jan 31.
Incentive pricing programs have potential to promote economically efficient water use patterns and provide a revenue source to compensate for environmental damages. However, incentive pricing may impose disproportionate costs and aggravate poverty where high prices are levied for basic human needs. This paper presents an analysis of a two-tiered water pricing system that sets a low price for subsistence needs, while charging a price equal to marginal cost, including environmental cost, for discretionary uses. This pricing arrangement can promote efficient and sustainable water use patterns, goals set by the European Water Framework Directive, while meeting subsistence needs of poor households. Using data from the Rio Grande Basin of North America, a dynamic nonlinear program, maximizes the basin's total net economic and environmental benefits subject to several hydrological and institutional constraints. Supply costs, environmental costs, and resource costs are integrated in a model of a river basin's hydrology, economics, and institutions. Three programs are compared: (1) Law of the River, in which water allocations and prices are determined by rules governing water transfers; (2) marginal cost pricing, in which households pay the full marginal cost of supplying treated water; (3) two-tiered pricing, in which households' subsistence water needs are priced cheaply, while discretionary uses are priced at efficient levels. Compared to the Law of the River and marginal cost pricing, two-tiered pricing performs well for efficiency and adequately for sustainability and equity. Findings provide a general framework for formulating water pricing programs that promote economically and environmentally efficient water use programs while also addressing other policy goals.
激励性定价方案有潜力促进经济高效的用水模式，并提供一种收入来源以补偿环境破坏。然而，激励性定价可能会带来不成比例的成本，并在对基本人类需求收取高价的情况下加剧贫困。本文分析了一种两级水定价系统，该系统为维持生计的需求设定低价，而对非必需用途收取等于边际成本（包括环境成本）的价格。这种定价安排可以促进高效和可持续的用水模式，这是欧洲水框架指令设定的目标，同时满足贫困家庭的生存需求。利用北美格兰德河流域的数据，一个动态非线性规划在若干水文和制度约束条件下使流域的总净经济和环境效益最大化。供应成本、环境成本和资源成本被整合到一个流域水文、经济和制度的模型中。比较了三个方案：（1）河流法，其中水分配和价格由水权转让规则决定；（2）边际成本定价，即家庭支付供应处理后水的全部边际成本；（3）两级定价，即家庭维持生计的用水需求定价低廉，而非必需用途定价在有效水平。与河流法和边际成本定价相比，两级定价在效率方面表现良好，在可持续性和公平性方面也表现尚可。研究结果为制定水定价方案提供了一个总体框架，该方案既能促进经济和环境高效的用水方案，又能实现其他政策目标。
