Sustainable saltwater intrusion management in coastal aquifers under climatic changes for humid and hyper-arid regions

Saltwater Intrusion (SWI) in many coastal areas is accelerated by freshwater boundary changes due to overpumping and decreasing aquifer recharge and sea-level rise. This study aims to control SWI due to the rise in sea levels in three climate regions: (i) humid and wet regions using storage dams at different heads and recharge ponds, (ii) hyper-arid and arid regions using physical barriers and wastewater treatment aquifer, brackish water abstraction, and desalination (TRAD) method, and (iii) semi-arid and semi-humid regions using a combination of flooding water recharge well-field and cut-off wall. The study was developed using the world benchmark problem of Henry's problem and Biscayne aquifer in the Cutler Ridge area near Deering Estate, Florida, USA. The finite-difference code SEAWAT was used in numerical simulations. The numerical results indicated that increasing the artificial recharge lake capacity minimizes the SWI in humid and wet regions with a high level of flooding. Moreover, the intrusion is mitigated using physical barriers and the TRAD method for hyper-arid and arid regions. Combining physical barriers during dry seasons and recharge wells for wet seasons resulted in suitable measures to managed the SWI in semi-arid and semi-humid regions. Finally, the best strategy to mitigate the SWI and minimize the desalination costs depends on the precipitation rates. Therefore, the methodology applied to this study represents a valuable tool in order to select the best method based on the climate conditions and particularly the precipitation intensity to increase the water budget in freshwater aquifers.

Automated summary

This study addresses the issue of saltwater intrusion accelerated by sea-level rise in different climate regions by proposing specific measures such as constructing reservoirs, physical barriers, artificial recharge, and desalination. Numerical simulations show that selecting appropriate strategies based on climate conditions can effectively reduce the risk of saltwater intrusion.