A Cost-Effective Method to Control Seawater Intrusion in Coastal Aquifers

Abstract

Intrusion of seawater into coastal aquifers is considered one of the most important processes that degrade water-quality by raising the salinity to levels exceeding acceptable drinking standards. Therefore saltwater intrusion should be prevented or at least controlled to protect groundwater resources. This paper presents a cost-effective method to control seawater intrusion in coastal aquifers. This methodology ADR (Abstraction, Desalination and Recharge) includes; abstraction of saline water and recharge to the aquifer after desalination. A coupled transient density-dependent finite element model is developed for simulation of fluid flow and solute transport and used to simulate seawater intrusion. The simulation model has been integrated with an optimization model to examine three scenarios to control seawater intrusion including; abstraction, recharge and a combination system, ADR. The main objectives of the models are to determine the optimal depths, locations and abstraction/recharge rates for the wells to minimize the total costs for construction and operation as well as salt concentrations in the aquifer. A comparison between the combined system (ADR) and the individual abstraction or recharge system is made in terms of total cost and total salt concentration in the aquifer and the amount of repulsion of seawater achieved. The results show that the proposed ADR system performs significantly better than using abstraction or recharge wells alone as it gives the least cost and least salt concentration in the aquifer. ADR is considered an effective tool to control seawater intrusion and can be applied in areas where there is a risk of seawater intrusion.

From the Problem of Ground Water Salinity towards Sustainable Prosperity in Agricultural Sector in Coastal Region of Gujarat, India

“…The mixing of saltwater with freshwater even in small quantities renders groundwater unsuitable for agricultural use [1]. The extension of seawater intrusion into coastal aquifers is a dynamic and interconnected phenomenon that depends on various factors such as recharge, coastal topography and groundwater abstraction from coastal aquifers [2] [3].…”

Managing the environmental problem of seawater intrusion in coastal aquifers through simulation–optimization modeling

“…The multiple management periods were considered since the hydraulic head and solute concentration can change significantly with time. A flow and solute transport simulation model was coupled with a GA-based management model by Abd-Elhamid and Javadi (2011). The model was used for the management of groundwater resources to predict the behavior of the system and provide optimal solution of seawater intrusion.…”

A Generalized Semi-Analytical Solution for the Dispersive Henry Problem: Effect of Stratification and Anisotropy on Seawater Intrusion

“…The mathematical formulation of the HP is based on the density-driven flow (DDF) model that incorporates a system of a variable density-flow equation, an advection-dispersion equation and a state relation, expressing the mixture density as function of the saltwater concentration. Because of the existence of this SA solution, HP has been accepted as one of the primary benchmarks for the assessment of DDF numerical codes, e.g., [6,[28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45].…”