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An analytical solution to Richards' equation for a draining soil profile
Author(s) -
Warrick A. W.,
Lomen D. O.,
Islas A.
Publication year - 1990
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/wr026i002p00253
Subject(s) - infiltration (hvac) , richards equation , thermal diffusivity , hydraulic conductivity , drainage , evaporation , water content , soil water , geotechnical engineering , thermodynamics , soil science , mathematics , geology , physics , ecology , biology
Analytical solutions are developed for the Richards' equation following the analysis of Broadbridge and White. Included here is the solution for drainage and redistribution of a partially or deeply wetted profile. Additionally, infiltration for various initial conditions is examined as well as evaporation at the upper boundary. In all cases the surface flux is constant, whether it be zero for drainage, positive for infiltration, or negative for evaporation. The solutions assume specific forms for the soil water diffusivity and hydraulic conductivity functions: a ( b − θ) −2 and β + γ( b − θ) + λ/[2( b − θ)], respectively. Here θ is the water content and a , b , β, γ, and λ are constants.