Investigation of flow within the capillary fringe using a synthetic aquifer

Abstract

An investigation of the ability of the tension saturated region of the vadose zone, known as the capillary fringe, to facilitate contaminant transport in the horizontal direction was investigated with a synthetic intermediate scale model aquifer. The synthetic aquifer model was designed for investigations of 2-D flow within the vadose zone by combining visual and instrument data in an automated data collection environment. The scope of the experiment included the establishment of steady state conditions, introduction of a conservative salt tracer and dye solution, and the flushing of the plume from a point source. A water table gradient was setup across the length of the model aquifer to establish horizontal flow below the water table and in the capillary fringe region. Results indicated that significant horizontal contaminant transport can occur within a capillary fringe region of the vadose zone.