In memory of Sjoerd van der Zee

On June 24, 2022, Sjoerd van der Zee, a great porous media scientist, passed away. He was a professor at Wageningen University and Research in The Netherlands, and an adjunct professor at the School of Chemistry of Monash University in Australia. After his retirement in July 2021, he was diagnosed with A.L.S., for which no cure is available.

Sjoerd was a renowned authority on the transport of impurities and pollutants in the natural environment, both from a theoretical (non-linear modelling) and experimental perspective. His research included the fate and transport of phosphates, heavy metals, pesticides and oil in natural soil-water-plant systems. He also contributed enormously to saltwater intrusion, changes in soil structure due to salinity and sodicity, waste water reuse, and the transport of emerging chemicals and heat in soils.

Through his studies, Sjoerd showed to be an expert in combining physical and chemical interactions of processes governing water flow and contaminant transport in soil and groundwater systems. Many of his mathematical studies were formulated within a stochastic framework to account for subsurface heterogeneity. He published more than 350 scientific articles, of which 220 appeared in peer-reviewed journals. He further contributed to many international conferences and institutional reviews, and coached more than 30 PhD students.

During InterPore2022, a minisymposium (“Porous Media for a Green World: Water & Agriculture”) was dedicated to Sjoerd van der Zee in recognition of his many contributions in research, student education and professional leadership.

Apart from his scientific qualities, Sjoerd was a great person to work with. He was interested in people and always ready to help. He was an amicable, creative, and modest person, but could also be vigorous and persistent in discussions. His great sense of humor was enjoyed by many.

He will be sorely missed.

Anton Leijnse, S. Majid Hassanizadeh, Rien van Genuchten