|Van Genuchten, Martinus|
Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 8/1/2005
Publication Date: 10/1/2005
Citation: Ramos, T.B., Van Genuchten, M.T., Goncalves, M.C., Martins, J.C., Pires, E.F. 2005. Parameter estimation of soil hydraulic properties from tension infiltrometr data in Portugal. In: S. Torkzaban and S. Majid Hassanizadeh (eds.), Proceedings of Workshop on HYDRUS Applications, p. 34-37, October 19, 2005, ISBN 90-39341125, Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands.
Technical Abstract: Mathematical models are increasingly used to address a broad range of variably-saturated flow and contaminant transport problems. Such simulations are generally based on numerical solutions of the Richards equation, which in turn require knowledge of the unsaturated soil hydraulic properties. These properties are often estimated from field-observed tension disc infiltrometer data. As an alternative to Woodings traditional analysis using an analytical solution for unconfined steady-state infiltration, the properties can be estimated also using numerical inversion methods such as those implemented in the HYDRUS-2D software package. The latter approach is based on minimization of an objective function during the parameter estimation process. Minimization of the objective function in HYDRUS-2D is accomplished using the Levenberg-Marquardt nonlinear minimization method. This brief document summarizes a recently study (Ramos et al., 2006, Vadose Zone Journal) in which we successfully tested the inverse modelling approach by analyzing the hydraulic properties of four field sites in Portugal. We compared the resulting hydraulic properties with independent estimates using Wooding’s analysis, as well as further interpreted the results in terms of soil macroporosity measurements.