Keywords

groundwater management, optimisation, pollution, decision support systems, optimal pumping pattern

Start Date

1-7-2004 12:00 AM

Description

Aquifer management is a complex problem in which various aspects should be taken into account. Specifically, there are conflicting objectives that should be achieved. On one side, there is the necessity to satisfy the water demand, on the other the resource water should be protected by infiltration of pollutants or substances that could reduce its availability in terms of short term and long term management. The aim of this paper is to develop a management model that is able to define the optimal pumping pattern for p (p=1,…,P) wells that withdraw water from an aquifer (characterized by pollutant contamination) and hydraulically interact, with the objectives of satisfying an expressed water demand and control pollution. In order to formalize and solve the management problem, it is necessary to consider the equations governing flow and mass transport of the biodegradable pollutants characterizing the aquifer. Such equations may be solved by using a finite-difference numerical scheme. In this work, the numerical scheme is embedded in the management model. The decision (control) variables that are considered in the optimisation problems are the water flows pumped at each well p, at time interval t. Such flows influence the state variables of the system, that is, the hydraulic head and the pollutant concentrations in the aquifer. The objective function to be minimized in the optimisation problem includes three terms: water demand dissatisfaction, pollutant concentrations in the extracted water, and pollutant concentrations in all cells of the discretized aquifer. Finally, the optimisation problem has been solved for a specific case study (Savona District, Italy), relevant to a confined aquifer affected by nitrate pollution deriving from agriculture activities.

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Jul 1st, 12:00 AM

Optimal Groundwater Exploitation and Pollution Control

Aquifer management is a complex problem in which various aspects should be taken into account. Specifically, there are conflicting objectives that should be achieved. On one side, there is the necessity to satisfy the water demand, on the other the resource water should be protected by infiltration of pollutants or substances that could reduce its availability in terms of short term and long term management. The aim of this paper is to develop a management model that is able to define the optimal pumping pattern for p (p=1,…,P) wells that withdraw water from an aquifer (characterized by pollutant contamination) and hydraulically interact, with the objectives of satisfying an expressed water demand and control pollution. In order to formalize and solve the management problem, it is necessary to consider the equations governing flow and mass transport of the biodegradable pollutants characterizing the aquifer. Such equations may be solved by using a finite-difference numerical scheme. In this work, the numerical scheme is embedded in the management model. The decision (control) variables that are considered in the optimisation problems are the water flows pumped at each well p, at time interval t. Such flows influence the state variables of the system, that is, the hydraulic head and the pollutant concentrations in the aquifer. The objective function to be minimized in the optimisation problem includes three terms: water demand dissatisfaction, pollutant concentrations in the extracted water, and pollutant concentrations in all cells of the discretized aquifer. Finally, the optimisation problem has been solved for a specific case study (Savona District, Italy), relevant to a confined aquifer affected by nitrate pollution deriving from agriculture activities.