A MATLAB program for estimation of unsaturated hydraulic soil parameters using an infiltrometer technique

TY - JOUR

T1 - A MATLAB program for estimation of unsaturated hydraulic soil parameters using an infiltrometer technique

AU - Mollerup, Mikkel

AU - Hansen, Søren

AU - Petersen, Carsten

AU - Kjærsgaard, Jeppe Hvelplund

PY - 2008

Y1 - 2008

N2 - We combined an inverse routine for assessing the hydraulic soil parameters of the Campbell/Mualem model with the power series solution developed by Philip for describing one-dimensional vertical infiltration into a homogenous soil. We based the estimation routine on a proposed measurement procedure especially suitable for early-time infiltrometer experiments where the flow can be considered as one-dimensional. The routine requires input of the initial soil water content and cumulative infiltration in two experiments with different pressures at the upper boundary and/or initial conditions. An independent measurement of the soil water content at saturation may reduce the uncertainty of estimated parameters. Response surfaces of the objective function were analysed. Scenarios for various soils and conditions, using numerically generated synthetic cumulative infiltration data with normally distributed errors, show promising results for finding the true values of the optimized parameters. We also investigated the effects of measurement frequency for the cumulative infiltration and errors in water content determinations.

AB - We combined an inverse routine for assessing the hydraulic soil parameters of the Campbell/Mualem model with the power series solution developed by Philip for describing one-dimensional vertical infiltration into a homogenous soil. We based the estimation routine on a proposed measurement procedure especially suitable for early-time infiltrometer experiments where the flow can be considered as one-dimensional. The routine requires input of the initial soil water content and cumulative infiltration in two experiments with different pressures at the upper boundary and/or initial conditions. An independent measurement of the soil water content at saturation may reduce the uncertainty of estimated parameters. Response surfaces of the objective function were analysed. Scenarios for various soils and conditions, using numerically generated synthetic cumulative infiltration data with normally distributed errors, show promising results for finding the true values of the optimized parameters. We also investigated the effects of measurement frequency for the cumulative infiltration and errors in water content determinations.

KW - Former LIFE faculty

KW - Philip infiltration equatation

KW - Campbell

KW - Mualem

KW - Least Squares

U2 - 10.1016/j.cageo.2007.12.002

DO - 10.1016/j.cageo.2007.12.002

M3 - Journal article

SN - 0098-3004

VL - 34

SP - 861

EP - 875

JO - Computers & Geosciences

JF - Computers & Geosciences

IS - 8

ER -