Groundwater and ecosystems damages: Questioning the Gisser-Sánchez effect

Gisser and Sánchez (1980a) state the conditions under which welfare gains from policy intervention are negligible in aquifer management, when compared with non-regulation or "free market" outcomes. This is the so-called Gisser-Sánchez effect (GSE), which has been supported by the ensuing literature during recent decades. The GSE requires a number of assumptions, among which is the disregard for aquatic ecosystems linked and dependent on aquifer systems. The depletion of aquifer systems in arid and semiarid regions worldwide is causing acute water scarcity and quality degradation, and leading to extensive ecosystem damages. This study shows that by including environmental damages into the analytical model, results can change substantially. The analysis highlights both theoretically and empirically the importance of policies in groundwater management, as well as the potential role for stakeholders' cooperation. The empirical application deals with two large aquifers in Spain, the Western La Mancha aquifer which is grossly mismanaged, and the Eastern La Mancha aquifer, which is moving towards sustainable management. Western and Eastern La Mancha aquifers illustrate that policies and institutions are essential to avoid the current global aquifer mismanagement.