HR: 16:05h
AN: H24A-01 INVITED     [Abstracts]
TI: John D. Hewlett (1922-2004) and the Variable Source Area Concept
AU: * Jackson, C R
EM: rjackson@forestry.uga.edu
AF: Warnell School of Forest Resources, University of Georgia, Athens, GA 30602-2152 United States
AB: Between 1961 and 1975, at least nine hydrologists contributed vitally to the development and promulgation of the variable source area concept, but John D. Hewlett had the honor of priority in describing the concept and coining the term. Hewlett's early hydrologic career focused on mountainous watersheds of the southern Appalachians, particularly watersheds within the Coweeta Hydrologic Laboratory, and thus his view of watershed behavior was developed in watersheds with steep slopes, highly infiltrative surface soils, strong boundaries of soil hydraulic properties, small valley aquifers, and flashy hydrographs. His efforts to explain the hydrologic behavior of these watersheds led him to focus on interflow and variable source area runoff as the drivers of stormflow, and his schematizations of hillslope behavior tied these two concepts together, with interflow delivering water to the base of slopes and the expansion and contraction of the valley aquifer creating variable source areas around the channels. In the 1970s, working with colleage C.A. Troendle, Hewlett struggled with incorporating the variable source area concept into rainfall-runoff models. Hewlett's understanding of the variable source area concept motivated him to push for hydrologic modeling tools that incorporated antecedent conditions, and he wrestled with research and modeling questions that still motivate research today. The history of the variable source area concept is an example of a ripe scientific concept being developed semi-independently by different investigators using different techniques over a relatively short period of time. While Hewlett laid much of the groundwork for this concept, it took the excellent cartographic presentation of the concept by Tom Dunne and Richard Black to popularize the variable source area concept in the hydrologic world.
DE: 1838 Infiltration
DE: 1860 Streamflow
DE: 1866 Soil moisture
DE: 1874 Ungaged basins
SC: Hydrology [H]
MN: Fall Meeting 2005