HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kool, J. B. Articles by van Genuchten, M. Th. Search for Related Content PubMed Articles by Kool, J. B. Articles by van Genuchten, M. Th. Agricola Articles by Kool, J. B. Articles by van Genuchten, M. Th.

Determining Soil Hydraulic Properties from One-step Outflow Experiments by Parameter Estimation: I. Theory and Numerical Studies¹

ABSTRACT

The numerical feasibility of determining water retention and hydraulic conductivity functions simultaneously from one-step pressure outflow experiments on soil cores by a parameter estimation method is evaluated. Soil hydraulic properties are assumed to be represented by van Genuchten's closed-form expressions involving three unknown parameters: residual moisture content , and coefficients and n. These parameters are evaluated by nonlinear least-squares fitting of predicted to observed cumulative outflow with time. Numerical experiments were performed for two hypothetical soils to evaluate limitations of the method imposed by constraints of uniqueness and sensitivity to error. Results indicate that an accurate solution of the parameter identification problem may be obtained when (i) input data include cumulative outflow volumes with time corresponding to at least half of the final outflow and additionally the final outflow volume; (ii) final cumulative outflow corresponds to a sufficiently large fraction (e.g., >0.5) of the total water between saturated and residual water contents; (iii) experimental error in outflow measurements is low; and (iv) initial parameter estimates are reasonably close to their true values.

¹ Contribution from the Dep. of Agronomy, Virginia Polytechnic Institute and State Univ., Blacksburg, VA 24061 and U.S. Salinity Laboratory, 4500 Glenwood Dr., Riverside, CA 92501.

² Research Associate and Associate Professor, Virginia Polytechnic Institute and State Univ., Blacksburg, VA 24061, and Research Soil Scientist, U. S. Salinity Laboratory, respectively.

Received for publication November 20, 1984. Accepted for publication June 6, 1985.

This article has been cited by other articles:

				J. D. Valiantzas, P. Londra, and A. Sassalou Explicit Formulae for Soil Water Diffusivity Using the One-Step Outflow Technique Soil Sci. Soc. Am. J., September 28, 2007; 71(6): 1685 - 1693. [Abstract] [Full Text] [PDF]

				N. Lazarovitch, A. Ben-Gal, J. Simunek, and U. Shani Uniqueness of Soil Hydraulic Parameters Determined by a Combined Wooding Inverse Approach Soil Sci. Soc. Am. J., May 16, 2007; 71(3): 860 - 865. [Abstract] [Full Text] [PDF]

				D. G. Meadows, M. H. Young, and E. V. McDonald A Laboratory Method for Determining the Unsaturated Hydraulic Properties of Soil Peds Soil Sci. Soc. Am. J., May 6, 2005; 69(3): 807 - 815. [Abstract] [Full Text] [PDF]

				S. Lambot, M. Antoine, I. van den Bosch, E. C. Slob, and M. Vanclooster Electromagnetic Inversion of GPR Signals and Subsequent Hydrodynamic Inversion to Estimate Effective Vadose Zone Hydraulic Properties Vadose Zone J., November 1, 2004; 3(4): 1072 - 1081. [Abstract] [Full Text] [PDF]

				S. Finsterle Multiphase Inverse Modeling: Review and iTOUGH2 Applications Vadose Zone J., August 1, 2004; 3(3): 747 - 762. [Abstract] [Full Text] [PDF]

				B. Minasny, J. W. Hopmans, T. Harter, S. O. Eching, A. Tuli, and M. A. Denton Neural Networks Prediction of Soil Hydraulic Functions for Alluvial Soils Using Multistep Outflow Data Soil Sci. Soc. Am. J., March 1, 2004; 68(2): 417 - 429. [Abstract] [Full Text] [PDF]

				H. Fujimaki, H. Fujimaki, and M. Inoue A Transient Evaporation Method for Determining Soil Hydraulic Properties at Low Pressure Vadose Zone J., August 1, 2003; 2(3): 400 - 408. [Abstract] [Full Text] [PDF]

				Z. F. Zhang, Z. F. Zhang, A. L. Ward, and G. W. Gee Estimating Soil Hydraulic Parameters of a Field Drainage Experiment Using Inverse Techniques Vadose Zone J., May 1, 2003; 2(2): 201 - 211. [Abstract] [Full Text] [PDF]

				J. A. Vrugt, J. A. Vrugt, W. Bouten, H. V. Gupta, and J. W. Hopmans Toward Improved Identifiability of Soil Hydraulic Parameters: On the Selection of a Suitable Parametric Model Vadose Zone J., February 1, 2003; 2(1): 98 - 113. [Abstract] [Full Text] [PDF]

				G. L. Butters, G. L. Butters, and P. Duchateau Continuous Flow Method for Rapid Measurement of Soil Hydraulic Properties: I. Experimental Considerations Vadose Zone J., November 1, 2002; 1(2): 239 - 251. [Abstract] [Full Text] [PDF]

				T.-C. J. Yeh and J. Simunek Stochastic Fusion of Information for Characterizing and Monitoring the Vadose Zone Vadose Zone J., November 1, 2002; 1(2): 207 - 221. [Abstract] [Full Text] [PDF]

				S. M. Hassanizadeh, M. A. Celia, and H. K. Dahle Dynamic Effect in the Capillary Pressure-Saturation Relationship and its Impacts on Unsaturated Flow Vadose Zone J., August 1, 2002; 1(1): 38 - 57. [Abstract] [Full Text] [PDF]

				L. Bruckler, P. Bertuzzi, R. Angulo-Jaramillo, and S. Ruy Testing an Infiltration Method for Estimating Soil Hydraulic Properties in the Laboratory Soil Sci. Soc. Am. J., March 1, 2002; 66(2): 384 - 395. [Abstract] [Full Text] [PDF]

				F. X. M. Casey and N. E. Derby Improved design for an automated tension infiltrometer Soil Sci. Soc. Am. J., January 1, 2002; 66(1): 64 - 67. [Abstract] [Full Text] [PDF]

				F. X.M. Casey and J. Simunek Inverse Analyses of Transport of Chlorinated Hydrocarbons Subject to Sequential Transformation Reactions J. Environ. Qual., July 1, 2001; 30(4): 1354 - 1360. [Abstract] [Full Text] [PDF]

				J.A. Vrugt, W. Bouten, and A.H. Weerts Information Content of Data for Identifying Soil Hydraulic Parameters from Outflow Experiments Soil Sci. Soc. Am. J., January 1, 2001; 65(1): 19 - 27. [Abstract] [Full Text]

				D. Wildenschild, J.W. Hopmans, and J. Simunek Flow Rate Dependence of Soil Hydraulic Characteristics Soil Sci. Soc. Am. J., January 1, 2001; 65(1): 35 - 48. [Abstract] [Full Text]

				Z.F. Zhang, R.G. Kachanoski, G. W. Parkin, and B. Si Measuring Hydraulic Properties Using a Line Source: II. Field Test Soil Sci. Soc. Am. J., September 1, 2000; 64(5): 1563 - 1569. [Abstract] [Full Text]

				Y. Mori, T. Maruyama, and T. Mitsuno Soft X-ray Radiography of Drainage Patterns of Structured Soils Soil Sci. Soc. Am. J., July 1, 1999; 63(4): 733 - 740. [Abstract] [Full Text]