Abstract
Measuring pressure induced water outflow in combination with inverse modeling is a suitable method to determine the hydraulic properties of soil columns. To study the dependence of the inverse method on the imposed experimental boundary conditions, cumulative water outflow from a soil column is simulated numerically. The column is assumed to be homogeneous with a height of 15 cm. Boundary conditions chosen for the bottom of the soil column are: one-step (OS), multi-step (MS) and linear (LPD) pressure decrease in time. Hydraulic properties are described by the closed forms proposed by van Genuchten (1980). Sensitivity coefficients for each of the parameters α, n, θ s , K s , and τ together with response surfaces for different parameter combinations are estimated for each of the boundary conditions. Then, the influence of random errors in the outflow data on the performance of the different boundary conditions is examined. It is shown that the MS-method is the only one resulting in unique estimates of all parameters investigated. The LPD- and MS-method are comparable if θ s and K s are not optimized simultaneously. The OS-method is very sensitive to the magnitude of the pressure step. A large step may lead to non-unique solutions of the inverse problem, caused by correlations between most of the parameters. Reducing the step leaves only the parameters n and θ s as not identifiable.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
Carrera, J., and Neumann, S.P. (1986) Estimation of aquifer parameters under transient and steady-state conditions: 2. Uniqueness, stability and solution algorithms, Water Resour. Res. 22, 211–227.
Celia, M. A., Bouloutas, E.T., and Zarba, R.L. (1990) A general mass-conservative numerical solution for the unsaturated flow equation, Water Resour. Res. 26, 1483–1496.
Draper, N.R., and Smith, H. (1981) Applied regression analysis, John Wiley&Sons, New York.
Durner, W. (1991) Vorhersage der hydraulischen Leitfähigkeit strukturierter Böden, Bayreuther Bodenkundliche Berichte 20 Bayreuth.
Eching, S.O., and Hopmans, J.W. (1993) Optimization of hydraulic functions from transient outflow and soil water pressure data, Soil Sci. Soc. Am. J. 57, 1167–1175.
Hornung, U,. and Messing, W. (1982) Identification of soil parameters for an infiltration problem, in K.P. Holz (ed.), Finite Elements in Water Resources 18, Springer, Berlin, pp. 15–24.
Hornung, U. (1983) Identification of nonlinear soil physical parameters from an input-output experiment, in P. Deuflhard and E. Hairer (eds.), Workshop on numerical treatment of inverse problems in differential and integral equations, Birkhauser, Bosten, pp. 227–237.
Koch, S. and Flühler, H. (1993) Solute transport in aggregated porous media: Comparing model independent and dependent parameter estimation, Water, Air and Soil Pollution 68, 275–289.
Kool, J.B., Parker, J.C., and van Genuchten, M.Th. (1985) Determining soil hydraulic properties from one-step outflow experiments by parameter estimation: I. Theory and numerical studies, Soil Sci. Soc. Am. J. 49, 1348–1354.
Kool, J.B., and Parker, J.C. (1988) Analysis of the inverse problem for transient unsaturated flow, Water Resour. Res. 24, 817–830.
Marquardt, D.W. (1963) An algorithm for least squares estimation of nonlinear parameters, J. Soc. Ind. Appl. Math. 11, 431–441.
Mualem, Y. (1976) A new model for predicting the hydraulic conductivity of unsaturated porous media, Water Resour. Res. 12, 513–522.
Russo, D., Bresler, E., Shani, U., and Parker, J.C. (1991) Analyses of infiltration events in relation to determining soil hydraulic properties by inverse problem methodology, Water Resour. Res. 27, 1361–1373.
Scheibke, R., Zurmühl, T., and Durner, W. (1991) Hochauflösende Datenerfassung zur Bestimmung der hydraulischen Eigenschaften ungestörter Bodensäulen, Mitteilgn. Dtsch. Bodenkundl. Gesellsch. 66, 217–220.
Schuh, W.M., and Cline, R.L. (1990) Effect of soil properties on unsaturated hydraulic conductivity pore-interaction factors, Soil Sci. Soc. Am. J. 54, 1509–1518.
Scotter, D.R., and Clothier, B.E. (1983) A transient method for measuring soil water diffusivity and unsaturated hydraulic conductivity, Soil Sci. Soc. Am. J. 47, 1068–1072.
Toorman, A.F., Wierenga, P. J., and Hills. R.G. (1992) Parameter estimation of hydraulic properties from one-step outflow data, Water Resour. Res. 28, 3021–3028.
Van Dam, J.C., Strieker, J.N.M., and Droogers, P. (1990) From one-step to multi-step: Determination of soil hydraulic functions by outflow experiments, Dep. of Hydrol., Soil Phys. and Hydraul., Rep. 7, Wageningen Agrie. Univ., Wageningen
Van Dam, J.C., Strieker, J.N.M., and Droogers, P. (1992) Inverse method for determining soil hydraulic functions from one-step outflow experiments, Soil Sci. Soc. Am. J. 56, 1042–1050.
Van Dam, J.C., Strieker, J.N.M., and Droogers, P. (1994) Inverse method to determine soil hydraulic functions from mulitstep outflow experiments, Soil Sci. Soc. Am. J. 58, 647–652.
van Genuchten, M.Th. (1980) A closed-form equation for predicting the hydraulic conductivity of unsaturated soils, Soil Sci. Soc. Am. J. 44, 892–898.
Yeh, W.W.-G. (1986) Review of parameter identification procedures in groundwater hydrology: The inverse problem, Water Resour. Res. 22, 95–108.
Zachmann, D.W., DuChateau, P.C., and Klute, A. (1982) Simultaneous approximation of water capacity and soil hydraulic conductivity by parameter identification, Soil Sci. 134, 157–163.
Zurmühl, T. (1994) Validierung konvektiv-dispersiver Modelle zur Berechnung des instationären Stofftransports in ungestörten Bodensäulen, Bayreuther Bodenkundliche Berichte 36, Bayreuth.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1996 Kluwer Academic Publishers
About this chapter
Cite this chapter
Zurmühl, T. (1996). Evaluation of Different Boundary Conditions for Independent Determination of Hydraulic Parameters Using Outflow Methods. In: Gottlieb, J., DuChateau, P. (eds) Parameter Identification and Inverse Problems in Hydrology, Geology and Ecology. Water Science and Technology Library, vol 23. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-1704-0_10
Download citation
DOI: https://doi.org/10.1007/978-94-009-1704-0_10
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-7263-2
Online ISBN: 978-94-009-1704-0
eBook Packages: Springer Book Archive