Modelling the dynamics of seal formation and pore clogging in the soil and its effect on infiltration using membrane fouling models

In the paper, we evaluated some of the prominent mathematical models derived from Darcy's law used to describe filtration membrane fouling occurring during the clarification of turbid fluids. The fouling can occur by basic mechanisms like surface pore blocking, pore constriction/obstruction, caking, or their combination. The paper presents a novel application of these models to the infiltration of overland flow into the soil. The soil, as a porous medium, is assumed to be the filter. The soil infilling that occurs during structural seal formation is assimilated to the membrane fouling process, and the turbid fluid is the flow enriched in fine particles due to the illuviation of the soil particles detached by raindrop impact and overland flow. Explicit mathematical equations were derived for the dynamics of the free surface area for infiltration, the resistance of the infiltration porous medium, the infiltration rate, the cumulative infiltration volume and the saturated hydraulic conductivity. The fluid characteristics and the validation dataset were provided by the SERLAB (Soil Erosion LABoratory, 42°59′34′’N 12°17′27′’E, Italy) of the University of Perugia and derives from a sequence of rainfall-simulation experiments in a silty clay loam. The better fits were obtained by combining the models that simulate the basic mechanisms of the free surface pore area blocking and the increase in the medium resistance due to pore obstruction by infilling fine particles. Both processes occur during structural crust formation. As a model reproducing the fine particles infilling pores both at the surface and at the underneath layer could describe the behaviour of the infiltration data, the contribution of this process should be added in modelling the dynamics of structural seal formation and its effect on infiltration