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Project title

A Geophysical and Geochemical Study of Submarine Groundwater Discharged in Galway Bay

Primary Funding Agency

Environmental Protection Agency (EPA)

Co-Funding Organisation(s)

n/a

Lead Organisation

Taighde Eireann Research Ireland (UoG)

Lead Applicant

Padraic Mac Donnacha

Project Abstract

Submarine groundwater discharge (SGD) refers to the movement of water from land to sea through underlying geology and the seabed. Quantifying SGDs from coastal karst aquifers such as the Burren is a significant challenge due to karst systems' complex and hidden nature. Unlike rivers or surface water flows, SGD occurs beneath the surface, often through diffuse or multiple discharge points, characterised by extensive networks of conduits, fractures, and caves, allowing for irregular and unpredictable groundwater flow paths, making it difficult to directly observe or measure where they enter the ocean. The spatial variability of karstic flow, coupled with factors such as tidal dynamics, sea level changes, and varying freshwater input, further complicates efforts to measure SGD accurately. The aim of this project is to build and expand on my MSc dissertation project which successfully identified a major and previously unknown SGD 800m off the coast of Blackhead in Galway Bay, with a focus on understanding its spatial distribution, salinity gradients, water chemistry, and impact on the surrounding marine environment. This project aims to develop a cost-effective and scalable methodology for identifying and quantifying SGD more widely, a process that is critical for managing coastal water quality and addressing contamination risks from nutrient and pollutant fluxes. The research involves multiple phases, including the analysis of high-resolution bathymetric data obtained from the INFOMAR project to detect sediment disturbances that may indicate SGD activity. This is followed by fieldwork, including the deployment of salinity loggers to monitor temporal variations in salinity and temperature, water chemistry analysis, seismic surveys and sediment sampling. Ultimately, the project seeks to advance the understanding of this SGD in Galway Bay and provide a methodological framework that can be applied to the Bay more widely, and other coastal regions, thereby contributing to more effective coastal monitoring and management strategies.

Grant Approved

€136,000.00

Research Hub

Delivering a Healthy Environment

Research Theme

n/a

Start Date

01/09/2025

Initial Projected Completion Date

31/08/2029