Deep sadness has been felt throughout the international hydrogeological community following the passing of Professor Joe Tóth, founder of the theory of regional groundwater flow systems, Professor Emeritus of the University of Alberta, Honorary Professor of Eötvös Loránd University, and external member of the Hungarian Academy of Sciences. He passed away on 3 July 2026 in Edmonton, Canada, in the 94th year of his life.
His pioneering scientific work fundamentally transformed modern hydrogeology and established the conceptual foundations for understanding groundwater flow systems at regional scales. His achievements were recognized through numerous international awards, including the O. E. Meinzer Award, the IAH President’s Award, the Robert N. Farvolden Award, the M. King Hubbert Science Award, and the C. V. Theis Award.
Throughout his life, Professor Tóth remained deeply committed to the international hydrogeological community and to supporting future generations of researchers. His scientific legacy continues through his publications, students, and the institutions and initiatives inspired by his work.
Words by Judit Mádl-Szőnyi – Chair of the Regional Groundwater Flow Commission
