Laboratory and field application of a twin disc infiltrometer

Smettem, K.R.J.ORCID: 0000-0003-2650-4429, Ross, P.J., Haverkamp, R., Parlange, J-Y and Gregory, P.J. (1998) Laboratory and field application of a twin disc infiltrometer. In: Dillon, P. and Simmers, I., (eds.) Shallow groundwater systems. A.A. Balkema, Rotterdam, Netherlands, pp. 41-51.

Abstract

A twin disc infiltrometer is employed to simultaneously measure one-dimensional and three-dimensional cumulative infiltration. The assumption that flow at early times is essentially one-dimensional can introduce error when estimating sorptivity, resulting in estimates that are greater than the true one-dimensional sorptivity. In contrast, sorptivity calculations using our recently developed three-dimensional infiltration equation give edge effect corrections that result in quite precise estimates of sorptivity in both laboratory and field tests. The estimates are shown to be consistent with measurements obtained from the buffered inner ring of the twin disc. The difference between three-dimensional and one-dimensional infiltration is used to calculate the value of the infiltration parameter, gamma, from the twin disc experiment in the laboratory. This parameter, together with the correct one-dimensional sorptivity, provide the information necessary to calculate the contribution of gravitational flow during three-dimensional infiltration. The laboratory test shows that when three-dimensional infiltration is dominated by capillary effects, as is often the case, estimation of hydraulic conductivity using quasi-steady-state solutions may not be possible. Results from the field test in a well aggregated topsoil illustrate dominance of the gravity term and show a general application of the method for obtaining parameters that describe three-dimensional infiltration.

Item Type:	Book Chapter
Publisher:	A.A. Balkema
Copyright:	© A.A. Balkema, Rotterdam
URI:	http://researchrepository.murdoch.edu.au/id/eprint/39150

Item Control Page