從經濟觀點論水資源管理

To View Water Resource Management from Economic Perspective

今年年初，臺灣面臨六十八年來最嚴重乾旱，並因此實施三階段限水措施。美國加州同樣遇到連續四年乾旱，而今年則是史上最乾旱的一年，所以也採取強制性減少用水的措施。這兩個地區都有各自的乾旱應變計畫，只是策略內容有些不同。由於乾旱危機的應變方式不同，不免引發決策是否受到相關資訊影響的聯想，而本文即認為，好的資訊是水資源管理決策能否達成較佳績效的關鍵。由於經濟學係在探討稀有資源配置的問題，所以對於解決水資源決策常碰到不同因素間取捨的難題，比較具有其優勢。為了做出明智的選擇，經濟學家必須評比他們考量的替選方案或選擇所引起的成本和效益。他們認為，選擇一定有成本，此即所謂白吃午餐的問題。此外，在經濟學家針對問題解決或是目標達成做出建議的政策前，他們必定使用經濟理論來幫助了解真實世界的運作。事實上，不僅經濟學有助於水資源管理做出較好決策，另一門學科──管理學──因為方法的不同，也可提供具互補性的資訊。

Taiwan was facing a most serious drought season in the past 68 years early this year, and a three stage limited water supply measure was proposed to deal with drought. At the same time, California State in the US was also experiencing four-year drought and the worst drought in its history, and a mandatory water use reduction was imposed. Though both regions have established their own drought contingency plan, the strategies are rather different. Following the drought crisis, the purpose of this paper is to advocate that good information for decisions in water resource management is critical to achieve better performance. Since economics is the study of the allocation of scarce resources, it has the advantage to address trade-offs among the disparate factors that are constantly encountered during decision making about water. In order to make wise choices, economists must compare the costs and benefits associated with each alternative or option they consider. They always think that their choices entail costs, the so-called free lunch. Besides, before economists can recommend any policies for dealing with problems or achieving goals, they must use economic theory to understand how the real world operates. As a matter of fact, not only economics is conducive to better decisions in water resource management, another discipline-science of management-is also important in complement with economics.