Soil Hydraulic Models Selection Based on In-Situ Measurements

Soil hydraulic properties are usually expressed as functional relationships between the soil hydraulic conductivity and water content or matric potential, and between the matric potential and water content. Both functions are highly nonlinear, and direct in-situ measurements are time consuming and involve considerable uncertainty. Therefore, methods based on soil hydraulic models, i.e., functions chosen a priori and containing parameters estimated from measurements, are of interest. The most widely used models are those of Gardner in 1958, Russo in 1988, Brooks and Corey in 1964, and van Genuchten in 1980. For such models, an equation is derived that relates the developed expression for the first moment, M, of the diffusivity function with a combination of measured parameters: saturated hydraulic conductivity, capillary length, saturation and residual water content, and soil sorptivity. The M expressions are derived for the three models in the form of explicit functions of their parameters. Three overlapp...

[1]  Wilfried Brutsaert,et al.  Some Methods of Calculating Unsaturated Permeability , 1967 .

[2]  J. Philip.  Inverse solution for one‐dimensional infiltration, and the ratio A/K1 , 1990 .

[3]  M. J. Sully,et al.  Macroscopic and microscopic capillary length and time scales from field infiltration , 1987 .

[4]  Y. Mualem.  A New Model for Predicting the Hydraulic Conductivity , 1976 .

[5]  Van Genuchten,et al.  A closed-form equation for predicting the hydraulic conductivity of unsaturated soils , 1980 .

[6]  Brent Clothier,et al.  Measurement of Sorptivity and Soil Water Diffusivity in the Field , 1981 .

[7]  J. R. Philip,et al.  Reply To “Comments on Steady Infiltration from Spherical Cavities , 1985 .

[8]  Brent Clothier,et al.  Measuring unsaturated sorptivity and hydraulic conductivity using multiple disc permeameters , 1989 .

[9]  J. Parlange,et al.  On Solving the Flow Equation in Unsaturated Soils by Optimization: Horizontal Infiltration , 1975 .

[10]  Jack C. Parker,et al.  Determining Soil Hydraulic Properties from One-step Outflow Experiments by Parameter Estimation: I. Theory and Numerical Studies1 , 1985 .

[11]  J. C. Parker,et al.  On the Correspondence between Brooks‐Corey and van Genuchten Models , 1989 .

[12]  R. Wooding,et al.  Steady Infiltration from a Shallow Circular Pond , 1968 .

[13]  W. R. Gardner.  SOME STEADY‐STATE SOLUTIONS OF THE UNSATURATED MOISTURE FLOW EQUATION WITH APPLICATION TO EVAPORATION FROM A WATER TABLE , 1958 .

[14]  J. Parker,et al.  Analysis of the inverse problem for transient unsaturated flow , 1988 .

[15]  A. Warrick,et al.  SORPTIVITY AND MACROSCOPIC CAPILLARY LENGTH RELATIONSHIPS , 1992 .

[16]  Uri Shani,et al.  Analyses of infiltration events in relation to determining soil hydraulic properties by inverse problem methodology , 1991 .

[17]  R. J. Hanks,et al.  Field method for estimating hydraulic conductivity and matric potential-water content relations , 1987 .

[18]  Jack C. Parker,et al.  Determining Soil Hydraulic Properties from One‐step Outflow Experiments by Parameter Estimation: II. Experimental Studies , 1985 .

[19]  Irene A. Stegun,et al.  Handbook of Mathematical Functions. , 1966 .

[20]  Peter Droogers,et al.  Inverse Method for Determining Soil Hydraulic Functions from One‐Step Outflow Experiments , 1992 .

[21]  David Russo,et al.  Determining soil hydraulic properties by parameter estimation: On the selection of a model for the hydraulic properties , 1988 .