Measuring saturated hydraulic conductivity and anisotropy of peat by a modified split-container method

摘要

Long-term changes in the physical and hydraulic properties of peat result from the decomposition and consolidation processes. The saturated hydraulic conductivity (Ks) of peat is depth-dependent and could increase or decrease with depth; therefore, Ks determination on a large number of samples is required to more accurately assess field variability. The cube method is a popular laboratory procedure to determine Ks because it allows use of smaller sample dimensions, while minimizing edge effects. This article describes the design and use of an alternate split container to enclose undisturbed peat cubes during measurement of Ks and the application of this method to a field site in Northwest Territories, Canada. The method allows for simpler and more controlled Ks measurements while also permitting anisotropy measurements. Matched tests on identical samples (Ks range 21-314 m/d), using the split-container and wax methods, showed a good agreement for intermediate Ks values; however, significant deviations occurred for low and high Ks values. Hydraulic-conductivity measurements taken on field samples showed a decrease with depth and exhibited anisotropic hydraulic conductivity as expected based on previous studies.