MEASUREMENT OF SOIL-WATER CONTENT DURING 3-DIMENSIONAL AXIAL-SYMMETRIC WATER-FLOW

Develops a method of measuring soil water content during three-dimensional axial-symmetric water flow in a laboratory column. A small plexiglass box with a pair of straight and a pair of curved, parallel transmission lines was constructed, packed with soil, saturated with water, and then left to dry out. Soil water content measurements using the time-domain reflectometry (TDR) method were made using both curved and straight transmission lines. A large laboratory flow box was also constructed with numerous curved TDR probes at different radial distances from one vertical edge of the box. The box was packed with soil and then water was applied from a small surface disc source, (radius = 15 mm) at the corner of the box. Soil water content was measured during the three-dimensional infiltration experiment. The method gave soil water content as a function of time for different radial distances from the point source, or the spatial distribution at different time intervals and can be used to test and study the theory of three-dimensional axial-symmetric flow of water into soil. -from Authors