Determination of the hydraulic characteristics of a cohesionless soil by means of the multicounter method

This paper gives a description of a newly developed technique for determination of both groundwater movement and the relative displacement of isotopes through porous media. The device automatically times the drift of a small radioisotope injection over a certain distance by means of four counting tubes. The flow direction is obtained from the time ratio between the peaks in the time-activity record. The velocity can furthermore be deduced knowing the direction and the distance from injection point to the center of the counting tubes distance which is constant. Measurement capability with this device is possible between 1 and 200 cm per day, giving an error within acceptable limits. Field and laboratory tests executed with this device were compared and calibrated by existing methods. Finally, some other applications are given.