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In Memoriam: Peter F. Germann

2021; Soil Science Society of America; Volume: 20; Issue: 2 Linguagem: Inglês

10.1002/vzj2.20111

1539-1663

Keith Beven,

Hydrology and Watershed Management Studies

Peter F. Germann Dear Editor: I am sad to report that Peter Germann died on 6 Dec. 2020 in Bern, Switzerland. Peter was well known to many soil hydrologists for his work on preferential flows—a career of research work that was summarized in his 2013 book on the subject published by the University of Bern (Germann, 2013). Peter had been a good friend since we first met at the Institute of Hydrology at Wallingford in 1979, where he spent a year as a post-doc and we found we had a common interest in preferential flows. Peter was born in St. Gallen Switzerland in 1944. He grew up in Bischofszell and later completed his schooling in St. Gallen. In 1963–1969, he studied for a Degree in Forestry at ETH Zurich and then stayed with Professor Richard to carry out research for a PhD at the Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft (WSL) from 1969 to 1976. He continued his work in the Laboratories of Hydraulics, Glaciology and Hydrology (VAW) during the period of 1976–1980. His PhD work was a study of the water relations on a forested slope in the Rietholzbach catchment based on maintaining a network of 35 nests of tensiometers at 10 different depths down to 3 m, set out on a triangular grid amongst the trees. At this time, these were still manual tensiometers coupled to mercury manometers that were read every two to three days for three years. One of the features that this remarkable dataset revealed was that during infiltration wetting could occur at depth in some cases, apparently bypassing the tensiometers above. Another was the large heterogeneity in responses between sites and between wetting events. Peter returned to Switzerland from Wallingford, and then in 1980 he took up a post as Assistant Professor in the Department of Environmental Sciences at the University of Virginia in Charlottesville where he stayed until 1986. He then moved as an Associate Professor to the Department of Soils and Crops at Rutgers University. In 1989, he was offered a Professorship at the Institute of Geography, University of Bern, back in Switzerland where he stayed until he retired in 2009. He held an Emeritus position at Bern until 2015. He continued to publish papers until shortly before his death, which followed two major strokes. For the major part of his research career, Peter was a strong advocate for a reconsideration of the physics of water flow through soils and, in particular, for the limitations of the Darcy–Buckingham–Richards flow theory that is based on an assumption of the equilibration of capillary potentials in some (not clearly defined) “representative elementary volume” of soil pores. Our common interested resulted in the highly cited review paper in Water Resources Research on macropores and water flow in soils in 1982 (later revisited in 2013), and a sequence of three papers in the Journal of Soil Science including a modeling approach based on kinematic wave theory that received very critical reviews. Some soil physicists at that time appeared to believe that the physics of soil physics had been solved. Peter later developed the kinematic wave approach into a theory of viscosity (rather than capillarity) dominated film flows subject to Stokes’ law during infiltration. Peter was a careful experimentalist, both in the laboratory and in the field, and made use of a variety of time domain reflectometry, sonic, and tracer experiments to study preferential flows. His thoughtful and good humored approach to collaborations, discussions, and presentations will be missed by many in soil science.