Application of linear programming and differential evolutionary optimization methodologies for the solution of coastal subsurface water management problems subject to environmental criteria

Δημοσίευση σε επιστημονικό περιοδικόSummarization: In the past optimization techniques have been combined with simulation models to determine cost-effective solutions for various environmental management problems. In the present study, a groundwater management problem in a coastal karstic aquifer in Crere, Greece subject to environmental criteria has been studied using classical linear programming and heuristic optimization methodologies. A numerical simulation model of the unconfined coastal aquifer has been first developed to represent the complex non-linear physical system. Then the classical linear programming optimization algorithm of the Simplex method is used to solve the groundwater management problem where the main objective is the hydraulic control of the saltwater intrusion. A piecewise linearization of the non-linear optimization problem is obtained by sequential implementation of the Simplex algorithm and a convergence to the optimal solution is achieved. The solution of the non-linear management problem is also obtained using a heuristic algorithm. A Differential Evolution (DE) algorithm that emulates some of the principles of evolution is used. A comparison of the results obtained by the two different optimization approaches is presented. Finally, a sensitivity analysis is employed in order to examine the influence of the active pumping wells in the evolution of the seawater intrusion front along the coastline.Presented on: Journal of Hydrolog

Optimal Management of an Overexploited Aquifer under Climate Change: The Lake Karla Case

This paper presents a study for finding the optimal management plan of an overexploited aquifer under global climate change. The study area is the aquifer of the basin of Lake Karla, located in the eastern part of Thessaly in Greece. An optimization method has been used to evaluate the optimum volume of water that can be extracted from the aquifer and the optimum position of the wells with the objective of water table rise to a desirable sustainable level, taking into consideration the climate change forcing. The modelling system consists of a series of interlinked models: a hydrological, a lake-aquifer, a reservoir operation, a groundwater, and an optimization model. The climate change forcing on precipitation and temperature has been evaluated using the outputs of Canadian Centre for Climate Model Analysis General Circulation Model (CGCMa2) and a hybrid downscaling method which combines a multiple regression (MLR) model and a timeseries model for two socioeconomic emissions scenarios. The results of this study show that climate change plays an important role, as it affects the optimum volume of the extracted groundwater and the position of the irrigation wells