GSI Groundwater Flood Data

December 2020

Groundwater flood data has been added to This data was prepared by Geological Survey Ireland (GSI), Department of Communication, Climate Action and Environment, in collaboration with Trinity College Dublin and the Institute of Technology Carlow for the GWFlood Project, 2016 – 2019.

The maps were prepared in order to address the deficit of groundwater flood data and to assist stakeholders to make scientifically informed decisions regarding groundwater flood risk in Ireland. The maps do not, and are not intended to, constitute advice. Professional or specialist advice should be sought before taking, or refraining from, any action on the basis of the flood maps.

For contextual information including Guidance Notes, Project Report and Project Website please see the links below:

Guidance Notes


Groundwater Flooding

Geological Survey Ireland

Groundwater floods occur when the water stored beneath the ground rises above the land surface. In Ireland, the most extensive form of groundwater flooding is related to prolonged rainfall causing water table rise in the limestone lowland areas in the west of the country.

The Groundwater Flood Probability Maps shows the probabilistic flood extent of groundwater flooding in limestone regions.  These maps are focussed primarily (but not entirely) on flooding at seasonally flooded wetlands known as turloughs. It should be noted that the predictive maps are limited to locations where the flood pattern was detectable and capable of being hydrologically modelled to a sufficient level of confidence.

The Maximum Historic Groundwater flood map shows maximum observed flood extents for locations of recurrent groundwater flooding in limestone regions. The map is primarily based on the winter 2015/2016 flood event, which in most areas represented the largest groundwater flood event on record.  The Winter 2015/2016 Surface Water Flooding map shows fluvial (rivers) and pluvial (rain) floods in Ireland, excluding urban areas, during the 2015/2016 flood event.