Tracing Vertical Translocation of Soil Moisture

Tracer experiments using 3_H tagged water were initiated during December 1972-January 1973 to determine the rate of downward displacement of water in an unsaturated Piedmont profile. Tritium location was monitored by daily soil sampling immediately after injection of activity and at frequencies decreasing to once every 6 months after 1 yr. At the end of 23 months the maximum level of activity was 24.8 ft (7.56m). The observed rate of movement will bring the maximum tritium activity to the water table level of 65 ft (20 m) in about 6 yr. Under conditions at the research site, lateral displacement of the materials was negligible. Some detention of activity in the high-clay B-horizon of the soil was observed.