2 Coastal Hydrogeology in an Age of Rising Seas

As sea levels rise, understanding hydrogeology is crucial in coastal areas. Seawater intrusion can lead to loss of potable or agricultural water supplies, and water table rise due to increasing sea level can lead to increased flooding and affect infrastructure.

Sunday, 19 October 2025
8:00 AM - 12:00 PM
HBGCC, 210AB

Coastal aquifer management during climate change: A critical evaluation of salinity barriers to control saltwater intrusion

Paper number: 2-14
Program: Technical Sessions
Time: 11:30 AM – 11:45 AM

Authors

Abstract

Sea level is expected to rise between 0.8 and 1.5 m before 2150. The sea level rise and associated increase in the frequency and duration of tropical storms (e.g., tidal surge events) will present challenges to the management of saltwater intrusion in coastal aquifers. One method of mitigating some effects of sea-level induced saltwater intrusion is the use of salinity barriers in the coastal zone. An evaluation was completed on eleven types of salinity barriers that could be used in unconfined and confined aquifers. The barrier types included physical barriers (curtain wall and grout curtains), infiltration canals filled with freshwater paralleling the coastline, injection barriers using  freshwater (treated surface water or wastewater), pumping or abstraction barriers, mixed injection and abstraction barriers, combined abstraction, desalination, and recharge (ADR) systems, ADR hybrid barriers using various water sources  including desalinated water and treated wastewater, compressed air barriers, aquifer storage and recovery dual use systems, biofilm barriers, and swelling clay or dispersion barriers. Six factors were considered in the evaluation including technology, environmental issues, regulatory issues, capital costs, and long-term effectiveness. In addition, the usefulness of all barrier types is impacted by local hydrogeology, aquifer hydraulic properties, and aquifer heterogeneity. The evaluation found that physical barriers and recharge canals may be ineffective in future control of saltwater intrusion in unconfined aquifers. Use of various configurations of injection and pumping barriers may be effective in unconfined aquifers only in coastal areas with steep landward slopes and in many confined aquifers. The new concept of using compressed air injection to control interface movement in confined aquifers merits future field testing and analysis.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412102

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