An Automated Tool for Three Types of Saturated Hydraulic Conductivity Laboratory Measurements

Acquisition of porous media saturated hydraulic conductivity data in the laboratory is usually time consuming and costly because of the manual labor associated with the currently available techniques. Lately, there has been increased interest in automating hydraulic conductivity laboratory techniques to reduce analysis time and improve data consistency. A new apparatus was developed that is able to measure hydraulic conductivity values with the constant-flux, constant-head, and falling-head methods in a fully automated fashion. The apparatus can be used for both packed columns and undisturbed field cores. The column design is such that water is forced to flow in a nominally one-dimensional manner through the porous medium. An analysis is initiated with a "smart search," yielding art estimate of the saturated hydraulic conductivity. The operator can use this estimated value to obtain conductivity values using one, two, or all three methods. Besides installing and removing the columns, no manual efforts are required. Hydraulic conductivity data for standard laboratory sands showed that application of the three methods resulted in similar results, indicating that external flow resistance was small. A comparison with literature data for the same sands, obtained with a constant-flux method, showed differences < 9%.