Planning Model for Optimal Control of Saltwater Intrusion

Abstract

A planning model is presented for the control of seawater intrusion in regional groundwater systems. The management model is structured as a problem in optimal control. The hydraulic response equations, which are developed from continuity principles, relate the movement of the interface to the magnitude and location of groundwater pumping and recharge. Finite difference methods are used to approximate the solution of the aquifer's response to management strategies. The control problem is solved using: (1) The influence‐coefficient method allied with quadratic programming; and (2) reduced‐gradient methods in conjunction with a quasi‐Newton algorithm. The planning model is applied to the Yun Lin groundwater basin in southwestern Taiwan where excessive pumping has produced declining water levels, localized land subsidence, and saltwater intrusion. The optimal groundwater pumping and recharge schedules for the Peikang area of the basin are presented. The computational efficiency of the algorithms is also discussed.