Experiment of Rainwater Infiltration Using an Undisturbed Soil Column

Abstract

Quick response of groundwater discharge to a heavy rain storm is a serious problem in Korea. An undisturbed soil-column experiment was conducted to consider the mechanism of rapid groundwater discharge during storm event in a weathered granite basin in Korea. The column was filled with undisturbed layered soil which represents the granite basin, and both precipitation and groundwater level were controlled. The layered structure was effective to store the infiltrated water on a boundary between the soil layers, and the amount of stored water was sufficient to increase the pore air pressure. The increased pore air pressure pushed out the groundwater, and this induced the rapid groundwater discharge. This phenomenon was observed only when the precipitation intensity was more than 40 mm/h and/or the upper soil layer was saturated with rainwater.