Optimal Pumping Schedule and Salinity Control in a Coastal Aquifer: a Decision Support System

Proper management of coastal wells is important in order to satisfy demand, minimize costs, control salinity increase, and ultimately to define water resource strategies which are both economically and environmentally sustainable.The optimal pumping schedule for a coastal well has been defined by a decision model that minimizes desalination and pumping costs, while taking into account the aquifer salinity levels near the well. The state equations are embedded as constraints in the optimization problem. Pumping is related to salinity via empirical response curves, through data collected in experimental campaigns. The decision model is defined as a multi-stage optimal control problem, which can be solved by applying dynamic programming. The architecture of a decision support system (DSS) for real time implementation in order to minimize costs and salinity increase is reported. A case study is presented with application to a well positioned at Kuki´o (Hawai´i Island, Hawai´i, USA).