International audiencetudying soil hydrological processes requires the determination of soil hydraulic parameters whose assessment using traditional methods is expensive and time-consuming. A specific method, Beerkan estimation of soil transfer parameters referred to as BEST was developed to facilitate the determination of both the water retention curve, {theta}(h), and the hydraulic conductivity curve, K({theta}), defined by their shape and scale parameters. BEST estimates shape parameters from particle-size distribution analysis and scale parameters from infiltration experiments at null pressure head. Saturated water content is measured directly at the end of infiltration. Hydraulic conductivity and water pressure scale parameters are calculated from the steady-state infiltration rate and prior estimation of sorptivity (S) This is provided by fitting transient infiltration data on the classical two-term equations with values from zero to a maximum corresponding to null hydraulic conductivity and using a data subset for which the two-term infiltration equations are verified as valid. BEST was compared with other fitting methods to estimate sorptivity and hydraulic conductivity from infiltration modeling data on the basis of the same infiltration equations for three contrasting soils: agricultural soil, sandy soil, and a coarser fluvioglacial deposit. The other methods failed sometimes to model accurately experimental data and to provide values in agreement with physical principles of water infiltration (negative values for hydraulic conductivity, too high steady-state infiltration rate). None of these anomalies was encountered when modeling cumulative infiltration with BEST. BEST appears to be a promising, easy, robust, and inexpensive way of characterizing the hydraulic behavior of soil

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This book summarises the main results of many contributions from researchers worldwide who have used the water infiltration process to characterize soil in the field. Determining soil hydrodynamic properties is essential to interpret and simulate the hydrological processes of economic and environmental interest. This book can be used as a guide to soil hydraulic characterization and in addition it gives a complete description of the treated techniques, including an outline of the most significant research results, with the main points that still needing development and improvement

Newer urban soils, frequently composed of several types of anthropogenic materials, may contain basic oxygen furnace (BOF) slag, which is a steel industry byproduct and considered a potential alternative material for road construction. An understanding of the flow and solute transfer processes through urban soils thus requires hydraulic characterization of these materials. The BEST (Beerkan Estimation of Soil Transfer Parameters) algorithm serves to estimate the full set of unsaturated soil properties by means of conducting an inverse analysis of Beerkan water infiltration data. This study aimed at characterizing unsaturated hydraulic properties of the BOF slag and its evolution during a 1‐yr period through water infiltration experiments and use of an adapted BEST method for inverse analysis. Results indicate the evolution with time of BOF slag hydraulic parameters due to their physicochemical changes when exposed to rainfall events. Moreover, the findings of this study highlight the initial spatial variability of hydrodynamic characteristics, which after a certain period shifts to mostly homogeneous behavior. This study has contributed to the hydrodynamic characterization of BOF slag by providing hydraulic conductivity and water retention curves, as required for modeling water and thus solute transfer processes vs. time, which is relevant to BOF slag reuse and environmental considerations.

[1] In this paper, a set of analytical infiltration equations that are commonly used to evaluate one-and three-dimensional water infiltration from a surface disc source is studied. Both the quasi-exact analytical formulation and the related approximations for short and long times are assessed. The analytical properties of the quasi-exact formulation are evaluated using a proposed scaling procedure in order to define the validity domains of related approximations. Both quasi-exact and approximate analytical equations are then studied with respect to their ability to reproduce numerically generated cumulative infiltrations from a 10 cm radius disc source for four soils (sand, loam, silt, and silty clay) at several initial saturations. The quasi-exact formulation is suitable for sand, loam, and silt when their soil-dependent and saturation-independent shape parameters, g and b, are properly chosen (between 0.75 and 1 and 0.3 and 1.7, respectively). Approximations derived for the same shape parameters can also be used, provided that their use is restricted to proposed validity intervals. However, none of these equations applies for silty clay, since its hydraulic properties do not fulfill the conditions required for the use of the quasiexact formulation.

International audienceWater movement in soil can be described accurately at the local scale, provided that soil hydraulic properties can be determined with precision. Traditional methods for characterizing soil are often time consuming, and large areas cannot be sampled easily. We present a simple method for overcoming these difficulties. It is easy to implement and cheap. It is known as the Beerkan method, and it relies on particle-size analysis, dry bulk density and simple infiltration tests in cylinders. We describe the experimental protocol and the method of data analysis, leading to the estimation of parameters describing hydraulic properties. Shape parameters depend on soil texture and are derived from particle-size data. Normalization parameters depend on soil structure. They are derived by inverse modelling and optimization from the infiltration tests. The theoretical background relies on the sorptivity concept and scaled forms of the infiltration equation. The formalism for one- and three-dimensional analysis is described. We assess the accuracy of the method using published data and simulated values, showing the soundness of the approach. For the purpose of illustration, we implemented a simple optimization technique on two bounding cases

International audienceThe hydraulic properties of the topsoil control the partition of rainfall into infiltration and runoff at the soil surface. They must be characterized for distributed hydrological modelling. This study presents the results of a field campaign documenting topsoil hydraulic properties in a small French suburban catchment (7 km2) located near Lyon, France. Two types of infiltration tests were performed: single ring infiltration tests under positive head and tension-disk infiltration using a mini-disk. Both categories were processed using the BEST--Beerkan Estimation of Soil Transfer parameters--method to derive parameters describing the retention and hydraulic conductivity curves. Dry bulk density and particle size data were also sampled. Almost all the topsoils were found to belong to the sandy loam soil class. No significant differences in hydraulic properties were found in terms of pedologic units, but the results showed a high impact of land use on these properties. The lowest dry bulk density values were obtained in forested soils with the highest organic matter content. Permanent pasture soils showed intermediate values, whereas the highest values were encountered in cultivated lands. For saturated hydraulic conductivity, the highest values were found in broad-leaved forests and small woods. The complementary use of tension-disk and positive head infiltration tests highlighted a sharp increase of hydraulic conductivity between near saturation and saturated conditions, attributed to macroporosity effect. The ratio of median saturated hydraulic conductivity to median hydraulic conductivity at a pressure of − 20 mm of water was about 50. The study suggests that soil texture, such as used in most pedo-transfer functions, might not be sufficient to properly map the variability of soil hydraulic properties. Land use information should be considered in the parameterizations of topsoil within hydrological models to better represent in situ conditions, as illustrated in the paper. Copyright © 2010 John Wiley & Sons, Ltd

International audienceUnderstanding particle mobilization and transport in soils is a major concern for environmental protection and water resource management as they can act as vectors for sorbing pollutants. In natural soils, the existence of a finite size and renewable pool of dispersible particles has been hypothesized. Even though freeze-thaw and wetting-drying cycles have been identified as possible mechanisms of pool replenishment between rainfall events, to date the underlying phenomena ruling the renewal of particle pools are still largely unexplored. We carried out a series of infiltration-drainage experiments to study systematically the effects of periods without rain (pauses) on in situ particle mobilization in undisturbed soil columns. We found that, for a given column, pause duration between two rainfall events has a major influence on subsequent particle mobilization: the mass of leached particles increases with pause duration until it reaches a maximum (mass for a 200-hours pause is 15 time greater than for a 1-hour pause), and then it decreases for even longer pauses. This behaviour was correlated with soil water content, and can be explained by soil matrix weakening due to differential capillary stresses during drying. The consequences of this finding are important because the 15-fold increase in mass of leached particles, when pause duration is changed from 1 hour to 4 days, might overwhelm variations caused by changes in other parameters such as the ionic strength of the incoming solution or the rainfall intensity