Optimal Management of a Coastal Aquifer in Southern Turkey

Abstract

Seven ground-water management models were developed to determine the optimal planning and operating policies of a costal aquifer in sourthern Turkey threatened by saltwater intrusion. Steady-state and transient finite-element simulation models, representing the response of the system, are linked to linear and quadratic optimization models using response functions. Optimal pumpage policies were determined for 94 wells under three management objectives that maximized agricultural water withdrawals and minimized drawdowns and pumping costs, subject to constraints related to the system's response equations; demand requirements; drawdown limitation in saltwater intrusion control locations and pumping wells; and discharge bounds. The results are shown in the form of trade-off curves relating optimal pumpage rates and pumping costs to basinwide drawdowns and saltwater containment. Modeling results indicate that significant increases in total aquifer yield are possible with controlled drawdowns so that infringement of saltwater is prevented. Optimal pumping schedules differed, depending on the type of objective function used. The best policy appears to be the one in which the excess water pumped from the most productive wells is transported overland to meet local demands at less productive wells.