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Can we distinguish Richards' and Boussinesq's equations for hillslopes?: The Coweeta Experiment revisited
Author(s) -
Steenhuis T. S.,
Parlange J.Y.,
Sanford W. E.,
Heilig A.,
Stagnitti F.,
Walter M. F.
Publication year - 1999
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/1998wr900067
Subject(s) - outflow , richards equation , point (geometry) , flow (mathematics) , boussinesq approximation (buoyancy) , mathematics , geology , geotechnical engineering , hydrology (agriculture) , meteorology , physics , geometry , water content , natural convection , convection , rayleigh number
Previous analyses of subsurface flow down sloping, shallow soil hillsides are further simplified. Surprisingly, whether the starting point is Richards' or Boussinesq's equation, the derived analytical expressions for cumulative outflow are identical, and they agree very well with experimental results from the Coweeta Hydrological Laboratory [ Hewlett and Hibbert , 1963]. We show that Boussinesq's model can be improved from a theoretical point of view at a very small cost. We also solved Boussinesq's equation numerically. However, this improved model did not fit the experimental data any better, while the numerical solution only showed a marginal agreement with the observed data.