ROLE OF MACROPORES IN SOIL WATER FLOW
The preferential flow under different simulated rainfall rates was studies on an undisturbed soil samples taken from the sandy-loam soil of Ulster County, New York. A four-segment outflow collector system was utilized for this column experiment. Chloride tagged water was also used as a flux to understand the role of macropores in solute transport. During the variable rate of rainfall events, water outflow volumes in different segments varied considerably. In fact, in one segment the measured outflow was negligible. However, during the higher rainfall intensities, the redistribution of outflow was observed due to increase in ponding height of rainwater. For example, in one segment the outflow volume decreased after fifty minutes by 5%. Although a uniform chloride concentration was applied, the outflow concentrations during the first five minutes were considerably different in different segments of the columns, suggesting the presence of preferential flow. In addition, Rhodamine dye was used to mark contaminant flow channels. The concentration of high flow areas, as marked by Rhodamine B dye, varied considerably from one segment to other.