Hydrogeological insights from groundwater level hydrographs in SE Ireland

• Published in: Quarterly journal of engineering geology and hydrogeology Vol. 45; no. 1; pp. 19 - 30
• Main Authors: Tedd, K. M, Misstear, B. D. R, Coxon, C, Daly, D, Hunter Williams, N. H
• Format: Journal Article
• Language: English
• Published: Geological Society of London 01.02.2012
• Subjects: aquifers; bedrock; climate change; gravel; monitoring; rivers; surface interactions; surface water; water table; watersheds; Ireland
• ISSN: 1470-9236
• DOI: 10.1144/1470-9236/10-026

Analysis of groundwater level records from Ireland’s South Eastern River Basin District (SERBD) allowed fundamental information about the nature of bedrock and gravel aquifers to be investigated. The hydrogeological setting of a monitoring point (with respect to, for example, recharge area, discharge area or proximity to a river) is the dominant factor influencing hydrograph character in bedrock aquifers, with aquifer type and subsoil properties producing secondary effects. Analysis of seasonal groundwater levels showed that the fractured bedrock aquifers recharge more quickly and typically have a longer recession period than gravel aquifers. The calculated recession periods for bedrock aquifers are longer than previous estimates for similar aquifers. Hydrograph analysis identified a number of notable phenomena including a gravel aquifer’s interaction with surface water and evidence of rejected recharge. Short-term groundwater level fluctuations caused by global seismic events, recorded via chart recorders, are discussed. Specific yield values were calculated, for a number of settings, from annual average groundwater level variations. The values supported estimates from previous research on similar aquifers. An analysis to investigate if any impacts of climate change were evident showed no consistent change in the timing of groundwater level minima or maxima.