Experimental and Modeling Investigation of Shallow Water Table Fluctuations in Relation to Reverse Wieringermeer Effect

Abstract

Soil column experiments and modeling investigations were performed to study the behavior of shallow water table in response to various recharge events. Hence, shallow water table fluctuations inside sandy (Toyoura sand) and clayey (Chiba light clay) soil columns in response to surface and sub-surface recharge events were investigated under laboratory conditions. Experimental results showed that small application of water could raise the shallow water table level more than 100 times in depth in the case of Toyoura sand and more than 50 times in the case of Chiba LiC, reflecting a reverse Wieringermeer effect (RWE) response type of groundwater. This rise was associated with a prompt change of pressure head values which exhibited instantaneous fluctuations of centimeters due to the addition of millimeters of water. The recharge volumes leading to such disproportionate water table rise were successfully estimated using a simple analytical model based on the moisture retention curve of the soil and considering the hysteresis effect on soil water dynamics within the capillary fringe zone.