CONSTRUCTION AND EVALUATION OF AN INEXPENSIVE WEIGHING LYSIMETER FOR STUDYING CONTAMINANT TRANSPORT

A description is provided of an above-ground, weighing lysimeter that minimizes the edge flow of water which can occur between the soil and the wall of the casing. The lysimeter was designed to study water flux and the movement of inorganic and/or organic pollutants as they pass through and beyond the root zone. The lysimeter is instrumented at sel ected depths with thermistors, soil solution extractors, time-domain r eflectometry probes, gas extractors and tensiometers. These sensors pr ovide temperature measurements, soil solution samples, water content m easurements, soil atmosphere samples and water potential measurements. The horizontal insertion of these instruments from the side of the ly simeter reduces any channeling that might occur along the sides of the instruments, if they had been inserted vertically. Annular-ring baffl es are located at selected depths to reduce edge flow between the lysi meter casing and the column of soil. The baffles redirect water flow a way from the edge of the column. Data an presented that show a reducti on in the hydraulic bypass of the lysimeter compared to a lysimeter wi thout baffles. The total cost of a single lysimeter including material s and labor is under US $4000.