Monitor the temporal and spatial evolution of clogging in a meso-scale lysimeter with tensiometers

Abstract:

In paddy fields or bioretention ponds, clogging occurs when surface water carrying suspended fine grains infiltrates into soils and forms a low permeability soil layer. The clogging layer significantly reduces the infiltration rate and could induce unsaturated zones and preferential flows. In this study, based on Darcy's law for layered soil, we developed a simple 1D equation to show the relationship between the clogging location and the soil water pressure head under different boundary conditions. In a vertical 1D domain, the response of the soil water pressure head to a decline in the adjacent groundwater level can indicate the occurrence and location of the clogging layer, even the unsaturated zone induced by the clogging layer. We analyzed a series of pressure data measured via a tensiometer installed in a meso-scale lysimeter during infiltration experiments under different clogging conditions. The data revealed the clogging development at the bottom of the lysimeter and its influence on the effective hydraulic conductivity evolution.