Data Acquisition System for Steady-State Hydraulic Soil Conductivity Measurements

This paper presents the design and construction of an automated single-ring infiltrometer for investigating soil hydraulic conductivity properties. The design is intended for increasing the quality and quantity of data, compared to manually recorded measurements, while reducing direct measurement time investment. The device consists of perspex pipe (Mariotte bottle with openings), a metallic ring, a differential pressure sensor and a programmable data acquisition system. The resolution obtained is better than 0.25mm for a 1 meter perspex pipe. Data from the infiltration process steady-state is then used for calculating the hydraulic conductivity. The infiltrometer unit was evaluated in different soil formations within the Cuitzeo lake watershed (19deg58´ N, 101deg08´ W). The measurements obtained with the automated unit are consistent, and improved, compared to manually recorded data.