Flume-scale laboratory study of rainfall-runoff responses in Devon silt and capillary barrier profiles

Abstract

The design of soil covers for mine waste reclamation requires comprehensive water balance calculations at the ground surface and the subsurface. To achieve a determinate water balance equation, rainfall-runoff quantities need to be predicted or measured. The parameters that control rainfall runoff were investigated by performing rainfall-runoff experiments on Devon silt and capillary barrier profiles at different saturation stages. A rainfall simulator apparatus was employed to measure water balance components at different rainfall intensities during each test; the apparatus’ design is presented. The rainfall intensity and the saturated hydraulic conductivity of the soil govern runoff volumes and rates in the saturated profiles. The rainfall intensity and infiltration capacity of the soil govern runoff volumes and rates in the unsaturated profiles. The capillary barrier effects are evaluated and discussed by comparing time-lapse photographs of the wetting front during each test with changes in matric suction and volumetric water content measurements.