In his presentation, Professor Baker made the point that much of the world relies on groundwater as a water resource, but that it is hard to know when and where rainfall actually replenishes our groundwater aquifers. Caves that are situated above the groundwater table are unique observatories of water transiting from the land surface to the aquifer. His lecture demonstrated that his experimental and analytical techniques using networks of loggers deployed in Australian caves (and mines and tunnels) have helped to understand when, where, and how much rainfall is needed to replenish the groundwater.
The presentation is now available on the Society's YouTube channel. Some images from the occasion are available at this link for viewing and downloading.