Determining soil saturated hydraulic conductivity and sorptivity from single ring infiltration tests

Abstract

The difference between the cumulative infiltration occurring during three-dimensional axisymmetric and one-dimensional vertical flow is a linear function of time. The slope of this line is a function of the source radius, initial and final volumetric soil water contents and the soil sorptivity. This allows the determination of the sorptivity and saturated conductivity of the soil from data of axisymmetric flow in a single ring of small diameter under negligible head of water. The method is based on the optimization of the sorptivity and saturated conductivity on the one-dimensional vertical cumulative infiltration inferred from axisymmetric flow data. To examine the reliability of the method to determine these parameters, numerical threeand one-dimensional data are generated on soils with known hydrologic properties from the literature. The linearity versus time of the difference of the two types of flow is verified. Several physically based expressions for the vertical cumulative infiltration as a function of time are considered. The optimized values of the sorptivity and saturated conductivity are compared to the their real known values. Despite the large errors on the optimized parameters, namely the saturated conductivity, the error on the vertical predicted cumulative infiltration is limited to 10%. This makes possible the application of this method on a large scale for hydrological modelling purposes.

Modeling effect of initial soil moisture on sorptivity and infiltration

“…The ratio C/K s is 1, depending on soil type and soil moisture [Philip, 1990], with proposed ranges of 1/3 C/K s 2/3 [Fuentes et al, 1992] or 0.3 C/K s 0.4 [Philip, 1990]. In the case of three-dimensional infiltration, C incorporates both saturated hydraulic conductivity and sorptivity [Smettem et al, 1995;Touma et al, 2007].…”

“…[6] Sorptivity represents the soil's ability to draw water [Philip, 1957b;Touma et al, 2007], which is a function of the capillarity (the driving force) and the soil's hydraulic conductivity (the dissipation). This dual-dependence is evident in Parlange [1975]'s precise solution for sorptivity (as modified for positive ponded conditions by Haverkamp et al [1990]):…”

Saturated Soil Hydraulic Conductivity

“…In particular, the method by Touma et al (2007) and the Simplified method based on the Beerkan Infiltration run (Bagarello et al 2013b(Bagarello et al , 2014b) rely on the so-called Beerkan experimental protocol and they consider the transient phase of an infiltration process under a constant head of water on the soil surface, theoretically equal to zero. With the Steady-State Falling-Head method by Elrick et al (1995) and the Bottomless Bucket method by Nimmo et al (2009), a falling-head infiltration process has to be established.…”

Caracterización de la infiltración de agua en tres sistemas de uso del suelo de la Comunidad Santiago de Carampoma, Huarochirí, Lima

“…El objetivo de estos muestreos es determinar y comparar las capacidades de los distintos usos de suelo para poder absorber agua en un proceso de humedecimiento y sin intervención de la gravedad. Touma et al (2007) indica que, para cuantificar la cantidad de agua infiltrada en función al tiempo después de aplicar agua a la superficie del suelo, solo se necesitan dos características del suelo: la conductividad saturada del suelo y la sortividad. La primera es la tasa máxima de flujo de agua debido únicamente a la gravedad en un suelo completamente saturado y es una propiedad intrínseca del suelo.…”