An automated infiltrometer for Beerkan measurements

Abstract

Soil hydraulic conductivity is a hydrodynamic parameter used to determine the infiltration capacity of water in a soil. To determine this parameter in the field, infiltration measurements and Beerkan tests are performed manually. These tests consist in inserting a cylinder with a known diameter into a horizontal soil to 1 cm depth, adding a known volume of water, and timing the infiltration time. Volumes of water are added manually until obtaining a constant infiltration time. It is important during this process to maintain a constant level of water inside the cylinder. However, this method has three major limitations: 1) the level of water varies between 5-10 mm and 0 mm and is therefore pseudo-constant (non-constant); 2) the manual addition of water requires the attention of an operator per test throughout the measurement, which can take several hours; lastly, 3) it includes an operator effect as the identification of the instant when the entire volume of water has infiltrated comprises an arbitrary element. Consequently, at the EMMAH laboratory, we have designed a prototype automated infiltrometer in view to ensuring the reliability of the measurements and improving the operator’s working conditions. This equipment, which permits automatically adding a volume of water in the cylinder, and measuring and recording the flow of water infiltrated, was validated by the first tests in-the-field.