Optimal Planning and Operation of Multiaquifer System

Abstract

Three ground‐water management models were developed to determine the optimal planning and operating policies of a multiaquifer system in eastern Saudi Arabia for an eight‐year planning period. The modeled system, which consisted of the Alat, Khobar, and Umm Er Radhuma aquifers, was represented by a three‐dimensional simulation model included in linear and quadratic optimization models using response functions. Yearly optimal pumping policies were determined for 52 well fields under three management objectives that maximized agricultural water withdrawals and minimized total drawdowns, and pumping costs subject to constraints related to the system's response equations, demand requirements, drawdown limitations, and discharge bounds. Multiobjective analyses were conducted to develop trade‐off curves relating increased agricultural water production to drawdown, aquifer dewatering, and pumping costs. Modeling results show the agricultural water production could be increased by almost two and a half times without causing dewatering. Optimal pumping schedules differed, depending upon the type of objective function employed. The best option appears to be the one in which extensive water transport is allowed between municipal well fields.