Jan 22, 2025: Ottawa SYP: Using Stable Isotopes to Delineate Groundwater Recharge at Different Spatial and Temporal Scales
Speaker: Alan Fryar
Abstract:
Since the 1960s, the stable isotopes oxygen-18 and deuterium have become widely used for delineating sources and timing of precipitation, identifying effects of evaporation, and apportioning end-member contributions in streamflow and groundwater. This talk reviews the use of water isotopes together with other parameters, particularly chloride (a conservative solute) and temperature, to delineate sources and timing of recharge in (1) regional sedimentary aquifer systems and (2) mountainous karst terrains. Case (1) studies focus on spatial variability in recharge, with implications for delineating diffuse versus focused recharge to surficial aquifers, paleorecharge to deep aquifers, and sources of geogenic contamination. Case (2) studies focus on temporal variability in individual spring basins, which may be particularly susceptible to climate change, and identifying recharge at event to seasonal time scales.
Speaker’s Bio:
Alan Fryar received his BS in Geology and History from Duke University in 1984, his MS in Geology from Texas A&M University in 1986, and his PhD in Geology from the University of Alberta in 1992. From 1992 to 1995, he was a Research Associate in the Bureau of Economic Geology at the University of Texas at Austin. He is a Professor of Earth and Environmental Sciences at the University of Kentucky, where he has been a faculty member since 1995. He teaches classes in hydrology, hydrogeology, and environmental geology, and he has graduated eight PhD and 18 MS advisees. His research encompasses groundwater/stream interactions; mass transport in karst watersheds; chemical evolution during groundwater recharge and flow; natural attenuation of contaminants; and water resources in developing countries. He is a Fellow of the Geological Society of America, was Chair of its Hydrogeology Division (2013-14), and is the Society’s Thompson International Distinguished Lecturer for 2024-25.
