Equity, Social Welfare, and Economic Benefit Efficiency in the Optimal Allocation of Coastal Groundwater Resources

There is increasing concern about groundwater scarcity, environmental problems, and its socio-economic consequences. Therefore, questions have been raised about new approaches to allocating groundwater resources. This study aims to shed new light on these debates through a modeling effort to be applied to coastal groundwater management (CGM). The purpose of this study is to develop an approach for modeling coastal groundwater allocation based on equity, social welfare, and economic benefit efficiency principles. In this approach, the Gini coefficient and a modified Bentham-Rawls Criterion have been applied to increase water allocation equity in water-using sectors and subareas. Moreover, both economic development and water management have been taken into account to improve economic benefit efficiency. Four benchmark CGM problems with different degrees of difficulty have been selected to examine a variety of objective functions and constraints in this approach. The results demonstrate that this approach can be applied to assess various situations in real-case and large-scale problems. Economic efficiency loss levels have a significant influence on agricultural and industrial water allocation equity and the maximum economic efficiency loss rate. In the agricultural and industrial sectors, a greater loss tolerance threshold means less economic benefit and more equal groundwater allocation. To improve groundwater allocation efficiency, some socio-economic requirements should be considered in CGM. The results indicate that water authorities need to strike a balance between equity and economic benefit in groundwater allocation to adapt to groundwater allocation problems.