Exploring groundwater drought responsiveness in lowland post-glacial environments

Abstract Groundwater drought response to meteorological forcing depends on initial hydrological conditions. This makes it difficult characterise groundwater droughts and identify the vulnerability of aquifers. The objective is increase understanding memory in lowland post-glacial environments. Eighty-one hydrographs are analysed, using standardised level index (SGI) precipitation index. Memory times assessed auto- cross-correlation functions. Response time estimated by comparing two approaches: (1) traditional use maximum cross-correlation, (2) alternative slope. Results interpreted for different hydrogeological settings. analysis showed that sand aquifers have longest times, particularly confined settings where could be over 4 years. Silts tills relatively short memories at less than 1 year, though median values silt higher unconfined In this study, estimating correlation slope superior capturing precipitation. However, results anomalies environments sometimes more influenced climate teleconnections concurrent forcing. emphasises need a holistic approach characterisation projection drought, as develops simultaneous timescales.