Sustaining Aquifers and their Water Economies

A long-established practice of managing aquifers relies on pumping restrictions to curtail drawdowns, in spite of their high economic impacts and the serious disputes that can follow such decisions. This paper applies an empirical, quantitative hydro-economic model that helps aquifer managers reverse aquifer drawdowns while minimizing the economic losses from pumping restrictions. We develop and present an innovative optimization framework for identifying pumping restrictions that minimize economic losses from current economic activities while eliminating the unsustainable threats from falling aquifers. We investigate several alternative measures to reduce economic costs of pumping limitations, including a proportional sharing of reductions across uses, several priority allocation methods, and permitted pumping caps augmented by permit trading. Results show that the largest reduction in costs of aquifer protection occurs when permitted pumping caps are combined with trading. The model is applied to improve management of two heavily-pumped aquifers in Kenya, but are generalizable to many aquifers worldwide experiencing unsustainable pumping.