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In situ measurements of soil saturated hydraulic conductivity: Assessment of reliability through rainfall–runoff experiments
Author(s) -
Morbidelli Renato,
Saltalippi Carla,
Flammini Alessia,
Cifrodelli Marco,
Picciafuoco Tommaso,
Corradini Corrado,
Govindaraju Rao S.
Publication year - 2017
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.11247
Subject(s) - infiltrometer , permeameter , hydraulic conductivity , environmental science , surface runoff , soil science , hydrology (agriculture) , calibration , plot (graphics) , infiltration (hvac) , soil water , meteorology , mathematics , statistics , geology , geotechnical engineering , ecology , biology , physics
Abstract The saturated hydraulic conductivity, K s , is a soil property that has a key role in the partitioning of rainfall into surface runoff and infiltration. The commonly used instruments and methods for in situ measurements of K s have frequently provided conflicting results. Comparison of K s estimates obtained by three classical devices—namely, the double ring infiltrometer (DRI), the Guelph version of the constant‐head well permeameter (GUELPH‐CHP) and the CSIRO version of the tension permeameter (CSIRO‐TP) is presented. A distinguishing feature in this study is the use of steady deep flow rates, obtained from controlled rainfall–runoff experiments, as benchmark values of K s at local and field‐plot scales, thereby enabling an assessment of these methods in reliably reproducing repeatable values and in their capability of determining plot‐scale variation of K s . We find that the DRI grossly overestimates K s , the GUELPH‐CHP gives conflicting estimates of K s with substantial overestimation in laboratory experiments and underestimation at the plot scale, whereas the CSIRO‐TP yields average K s values with significant errors of 24% in the plot scale experiment and 66% in laboratory experiments. Although the DRI would likely yield a better estimate of the nature of variability than the GUELPH‐CHP and CSIRO‐TP, a separate calibration may be warranted to correct for the overestimation of K s values. The reasons for such discrepancies within and between the measurement methods are not yet fully understood and serve as motivation for future work to better characterize the uncertainty associated with individual measurements of K s using these methods and the characterization of field scale variability from multiple local measurements.