Rapid measurement of field-saturated hydraulic conductivity for areal characterization

To provide an improved methodology for characterizing the field‐saturated hydraulic conductivity (K_fs) over broad areas with extreme spatial variability and ordinary limitations of time and resources, we developed and tested a simplified apparatus and procedure, correcting mathematically for the major deficiencies of the simplified implementation. The methodology includes use of a portable, falling‐head, small‐diameter (∼20 cm) single‐ring infiltrometer and an analytical formula for K_fs that compensates both for nonconstant falling head and for the subsurface radial spreading that unavoidably occurs with small ring size. We applied this method to alluvial fan deposits varying in degree of pedogenic maturity in the arid Mojave National Preserve, California. The measurements are consistent with a more rigorous and time‐consuming K_fs measurement method, produce the expected systematic trends in K_fs when compared among soils of contrasting degrees of pedogenic development, and relate in expected ways to results of widely accepted methods.