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The relevance of measuring saturated hydraulic conductivity : sensitivity analysis and functional evaluation

Journal Contribution - Journal Article

The saturated hydraulic conductivity (K-s) is considered to be one of the main soil hydraulic properties to simulate water transport in the vadose zone, yet it is notoriously difficult to assess due to its large field-scale variability and sensitivity to preferential flow paths. With the increasing availability of convenient methods to measure the unsaturated hydraulic conductivity (K-u), the additional value of measuring K-s could be questioned. This study investigates the relevance of measuring K-s in two ways. Firstly, a sensitivity analysis was performed to evaluate which part of the hydraulic conductivity curve impacts the simulation of unsaturated water transport most. It was found that hydraulic conductivity curve between -10 cm and -1000 cm matric head was affecting the simulation more than at saturation. Secondly, a functional evaluation was performed by simulating water flow in six test fields according to three scenarios, in which the hydraulic properties were determined with the measured K-s and/or K-u. The simulation of saturation degree at three depths was the least accurate in the scenario where only K-s was measured. Remarkably, the most accurate simulation was found in the scenario with only the measured K-u. According to these results, measuring K-u would be of greater importance than measuring K-s for the simulation of water flow in the vadose zone.
Journal: Journal of Hydrology
ISSN: 0022-1694
Volume: 576
Pages: 628 - 638
Publication year:2019
Keywords:Environmental science & technology, General & traditional engineering, Geosciences & technology