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

Flooding Beneath and Beyond: Groundwater Pathways of Contaminant Mobilization in Texas’ Unincorporated Coastal Communities

Paper number: 2-1
Program: Technical Sessions
Time: 8:05 AM – 8:25 AM

Authors

Abstract

The Texas Gulf Coast presents a hydrogeologically diverse landscape where shallow aquifers, extreme weather, and rising seas converge to intensify groundwater-driven risks. Our research across multiple NSF-, EPA-, and NOAA-funded projects reveals that submarine groundwater discharge (SGD), aquifer responses to flooding, and contaminant mobilization are critical but underrecognized processes influencing coastal water quality. This presentation synthesizes findings from unincorporated communities situated in both semi-arid and humid coastal settings, including barrier islands, bay-adjacent areas, and inland colonias, where infrastructure limitations amplify vulnerability to groundwater contamination. Case studies from the semi-arid Coastal Bend to the humid barrier island systems of the upper Texas Gulf Coast demonstrate how extreme wet events can shift redox conditions, overwhelm septic systems, and mobilize both legacy and emerging contaminants. While some studies highlight the role of water table rise in surfacing pollutants, others emphasize broader hydrogeochemical changes driven by seasonal dynamics and compound flooding. Field geophysics, stable and radiogenic isotopes, deep learning, and geochemical modeling provide insight into both chronic and episodic pollution pathways. I will also share recent results on arsenic and nutrient fluxes and discuss their implications for water security and public health in underserved communities. This work is grounded in close collaboration with residents and resource managers through co-development of knowledge and community-informed decision-making frameworks. Together, these efforts underscore the urgent need to integrate subsurface processes into coastal flood planning, infrastructure design, and equitable water policy.

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

doi: 10.1130/abs/2025AM-413528

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