Optimal Allocation of Ground and Surface Water in O'ahu: Water Wars in Paradise

Despite abundant rainfall and groundwater resources, the State of Hawai'i has managed to erect so many barriers to efficient use that serious conflicts have erupted over use rights to water. In what is currently the most prominent battle, environmental and agricultural interests of windward O'ahu are pitted against agricultural producers on the leeward side over the allocation of aqueduct water in the Koolau Mountains. To inform this debate, a model of conjunctive use is constructed and optimal allocation of ground, surface and aqueduct water computer. Optimal use of the aqueduct water is as a substitute for groundwater. This postpones the eventual, expensive use of desalination, thus benefiting future users. By making use rights fully transferable and charging current users water's true opportunity cost, both windward and leeward users would be winners.