Perceptual Models in Catchment Hydrology

Most catchment hydrologists use models—to solve problems and predict outcomes and change. But those models are often based on quite antiquated notions of how catchments store and release water. This talk will outline of what we know, what we think we know and what we need to know in terms of the flow pathways, sources and travel times of water through headwater catchments. It covers the period from the first field-based process measurements in the early 20th Century to the development of early rainfall-runoff concepts, the great geographic expansion of studies during the First International Decade and the radial shifts in understanding resulting from the use of isotope tracers in catchment hydrology. It then covers our modern understanding of how catchments store and release water at the point-, hillslope- and catchment-scales and how bottom-up and top-down measures can be used to diagnose catchment function. It ends with discussion of the opportunities and challenges for what remains to be discovered in terms of hydrological connectivity, the sources, residence times and transit time distributions of catchments flows and the mechanistic tug of war between stream flow and the plant transpiration outflow The throughline of talk is that field discovery is an essential part of hydrological science and that what remains to be discovered about the age, origin and pathways of water is vast compared to what is now known.

Bio: Jeffrey McDonnell is a University Distinguished Professor of Hydrology and Associate Director of the Global Institute for Water Security at the University of Saskatchewan. He is the winner of the 2016 the International Hydrology Prize from the International Association of Hydrological, UNESCO and the World Meteorological Organization and 2009 Dalton Medal from the European Geosciences Union. McDonnell is a member of the Royal Society of Canada, the American Association for the Advancement of Science and Academia Europaea. He is a fellow of the American Geophysical Union, the Geological Society of America and the Royal Geographical Society. He has been the recipient of numerous awards, among them the Outstanding Achievement Award of the New Zealand Hydrological Society, the Ray K. Linsley Award for Surface Water of the American Institute of Hydrology, the Gordon Warwick Medal of the British Society for Geomorphology and the Scientific and Technological Achievement Award from the US Environmental Protection Agency. He is the former President of the AGU Hydrology Section and author of the book “Navigating an Academic Career: A Brief Guide for PhD Students, Postdocs and Early Career Faculty”.