296 Innovations in Research of Groundwater-Surface Water Interactions over Multiple Spatio-Temporal Scales (Posters)

This session will focus on fluxes of water and solutes between groundwater and surface water, which play a crucial role in freshwater supplies for humans and ecosystems.

Wednesday, 22 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Investigating Groundwater and Surface Water Interactions in Galveston Bay, Texas Across Spatial and Temporal Scales

Paper number: 296-0
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Understanding groundwater and surface water interactions is essential for identifying hidden pathways of contaminant transport in coastal environments. Galveston Bay, the largest estuary in Texas, is influenced by diverse land uses, including industrial, urban, and natural areas, all of which contribute to the complexity of potential pollutant sources. While surface water inputs have been extensively monitored, subsurface contributions remain undercharacterized. This study explores the spatial and temporal variability of coastal groundwater discharge and its interaction with surface waters across multiple sites, including the main freshwater inlets into the bay (Clear Creek, Dickinson Bayou, Buffalo Bayou, San Jacinto River, and Trinity River), and along the bay’s coastal margins. Preliminary data collected from radon-based assessments indicate groundwater fluxes averaging 14 cm/day, with maximum values reaching 305 cm/day. Discharge peaks during low tide, indicating that tidal pressure affects groundwater release. Higher groundwater discharge was observed in upstream areas, likely due to fewer urban infrastructures and slightly higher topography compared to downstream areas. To further resolve the sources and nature of these inputs, a radium mass balance will be used to separate terrestrial freshwater from recirculated seawater. The outcomes of this study are expected to enhance understanding of subsurface pollutant pathways and support the development of targeted coastal water quality management strategies.

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

doi: 10.1130/abs/2025AM-412711

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