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Title: Quantifying the effect of subcritical water repellency on sorptivity : a physically based model
Authors: Shillito, Rose M.
Ghezzehei, Teamrat A.
Berli, Markus
Keywords: Soil water dependency
Contact angle
Post-fire runoff
Publisher: Coastal and Hydraulics Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Miscellaneous Paper (Engineer Research and Development Center (U.S.)) ; no. ERDC/CHL MP-21-1
Is Version Of: Shillito, Rose M., Markus Berli, and Teamrat A. Ghezzehei. "Quantifying the Effect of Subcritical Water Repellency on Sorptivity: A Physically Based Model." Water Resources Research 56, no. 11 (2020): e2020WR027942.
Abstract: Soil water wettability or water repellency is a phenomenon that can affect infiltration and, ultimately, runoff. Thus, there is a need to develop a model that can quantitatively capture the influence of water repellency on infiltration in a physically meaningful way and within the framework of existing infiltration theory. The analytical model developed in this study relates soil sorptivity (an infiltration parameter) with contact angle (a direct measure of water repellency) for variably saturated media. The model was validated with laboratory experiments using a silica sand of known properties treated to produce controlled degrees of water repellency. The measured contact angle and sorptivity values closely matched the model‐predicted values. Further, the relationship between the frequently used water drop penetration time test (used to assess water repellency) and sorptivity was illustrated. Finally, the direct impact of water repellency on saturated hydraulic conductivity was investigated due to its role in infiltration equations and to shed light on inconsistent field observations. It was found that water repellency had minimal effect on the saturated hydraulic conductivity of structureless sand. A quantitative model for infiltration incorporating the effect of water repellency is particularly important for post‐fire hydrologic modeling of burned areas exhibiting water repellent soils.
Description: Miscellaneous Paper
Gov't Doc #: ERDC/CHL MP-21-1
Rights: Approved for Public Release; Distribution is Unlimited
Appears in Collections:Miscellaneous Paper

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