Author
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Van Genuchten, Martinus |
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Submitted to: American Geophysical Union
Publication Type: Abstract Only Publication Acceptance Date: 8/15/2006 Publication Date: 11/28/2006 Citation: Van Genuchten, M.T. 2006. One Century of Unsaturated Zone Hydrology: Then, Now, But What Next?. American Geophysical Union Fall Meeting San Francisco, CA Dec 11-15, 2006. Paper No. H54-A-03 Interpretive Summary: Technical Abstract: Buckingham's 1907 paper on the movement of soil moisture is viewed by many as the foundation of unsaturated zone hydrology. Buckingham's work came at a time when most studies in soil physics focused on field soil water status, water retention, evaporation and especially the physical environment of plants. Theoretical studies of water, heat and solute movement in soils slowly matured subsequently, eventually leading to the formulation and use of partial differential equations for subsurface flow and transport, exemplified by the Richards equation in 1931. Analytical and numerical studies slowly followed also, with the work increasingly focusing on environmental and hydrological applications, in addition to agriculture. In this presentation we briefly reflect upon some of the initial developments in vadose zone hydrology, and on the explosion of information during especially the past 20 years or so, but then offer a very speculative look at what may be next. Continued areas of research will likely focus (or should focus) on better integration of physical and biogeochemical processes, coupling surface and subsurface flow processes, increased pore-scale modeling with applications to larger-scale problems, the environmental fate of emerging contaminants, continued struggles with subsurface heterogeneity and preferential flow, and more ingenious integration of geophysical and computational tools with direct measurements and inverse methods. While the current state of vadose zone hydrology was likely unimaginable 100 years ago, so are the environmental problems we now are facing on this Earth. This makes it also important to narrow the increasingly larger gap between the state- of-the-art and state-of-the-practice. |
