QUASI-3-DIMENSIONAL OPTIMIZATION MODEL OF JAKARTA BASIN

An optimization model for the control of saltwater intrusion in the Jakarta Multiple aquifer system is presented. The optimization model incorporates a quasi-three-dimensional, finite-difference simulation model of the aquifer system. The ground-water systems are hydraulically coupled via leakage into or out of each aquifer. Finite-difference methods are used to generate the hydraulic-response equations of the ground-water basin relating, for each aquifer, the freshwater and saltwater heads, the location of the interface, and the pumping and recharge schedules. The optimization model minimizes the total squared volume of saltwater in each aquifer of the ground-water system; the control variables of the model are the location and magnitude of ground-water pumping and recharge. The model is required to satisfy the current water demand in the basin. The optimization model is solved using MINOS, a projected Lagrangian algorithm, and a modified gradient procedure based on Box's algorithm. The underlying simulation equations are incorporated in each optimization algorithm; the algorithm evaluates the simulation equations to determine the objective and constraint gradients of the planning problem. Planning results are presented. Parametric programming is used to determine the trade-offs affecting the optimal decisions.