Using Compressed Air Injection to Control Seawater Intrusion in a Confined Coastal Aquifer

Dong-mei Sun*, Stephan Semprich

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Seawater intrusion into groundwater is an important problem in many coastal regions. Freshwater injection has been widely used to avoid seawater contaminating freshwater systems, but is not an attractive solution where freshwater is limited. We investigated the effects of injecting compressed air on seawater movement in a confined coastal aquifer using a numerical simulation. We used TOUGH2/EOS7 software to analyze the effects of injecting compressed air in preventing seawater intruding into a hypothetical confined coastal aquifer (Henry’s problem), simulating steady-state initial conditions and comparing the results with the literature sources. We then performed a transient-state numerical simulation to quantify the seawater intrusion control efficiency achieved by injecting air. The results showed that injecting compressed air can mitigate seawater intrusion: Saltwater was ejected from the aquifer and the seawater circulation disappeared. The injected air flowed upward and spread laterally near the top of the aquifer because of the groundwater and air densities. Injecting air significantly increased the groundwater and gas pressures near the air injection zone and at the top of the aquifer. The air injection rate increased rapidly, then increased gradually. Freshwater injection was also simulated using settings similar to those used for air injection, and this showed that seawater intrusion is prevented more efficiently by freshwater injection than air injection. However, freshwater resources are valuable, whereas air is readily available, so injecting air to mitigate seawater intrusion has great potential. The modeling approach that we used will be used as a foundation for future work.
Original languageEnglish
Pages (from-to)259-278
Number of pages19
JournalTransport in Porous Media
Volume100
Issue number2
DOIs
Publication statusPublished - 2013

Keywords

  • Groundwater
  • Seawater intrusion
  • Compressed air injection
  • Numerical simulation

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Computational Mechanics
  • Environmental Engineering

Fields of Expertise

  • Sustainable Systems

Treatment code (Nähere Zuordnung)

  • Application
  • Theoretical

Fingerprint

Dive into the research topics of 'Using Compressed Air Injection to Control Seawater Intrusion in a Confined Coastal Aquifer'. Together they form a unique fingerprint.

Cite this