ABSTRACT
Field measurements of profiles of water content in the sandy phreatic Coastal Plain aquifer of Israel, north of the city of Tel Aviv, revealed that the distribution of water within the capillary fringe (CF) was compact, meaning that there was an abrupt change in water content with increasing height above the water table (the plane at which pressure p = 0). At the study site the aquifer is composed of relatively homogeneous sandy sediments, the water table is at a depth of 7 m and recharge is the result of rain infiltration only. The water content as a function of depth was obtained from continuous cores in 13 boreholes, twelve of which were located within a radius of 5 m. It was found that the average height of the CF above the water table was about 1.4 m, and over a horizontal distance of about 4 m this height (at each point above the water table) varied by up to 33% and 50% before and after the rainy season, respectively. The distribution of water in the CF remained compact while being displaced vertically as the water table rose 35 cm after the winter rains. These observations are consistent with pore level models of the water distribution within the capillary fringe in a porous media (Ronen et al. 1997).
