Award Date

5-1-2020

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Geoscience

First Committee Member

Markus Berli

Second Committee Member

Teamrat Ghezzehei

Third Committee Member

Elisabeth Hausrath

Fourth Committee Member

Ganqing Jiang

Fifth Committee Member

Dale Devitt

Number of Pages

85

Abstract

Soil water repellency (SWR) is believed to contribute to the increased potential for post-fire runoff and erosion. Currently, no quantitative method exists to account for SWR in physically-based runoff models. A physically-based model incorporating SWR (through the contact angle) in the infiltration parameter, sorptivity, was developed. The model was tested and verified with controlled laboratory tests on a fully characterized sand treated to create various degrees of SWR. The ability to create the wetting water characteristic curve for untreated and treated sand, appropriate for the infiltration process, was presented. Additionally, the ability to measure sorptivity with widely used infiltration tests was assessed. The model predicted sorptivity response to SWR remarkably well. The model was also able to account for the effect of initial water content on sorptivity. SWR-altered sorptivity had a greater effect on cumulative infiltration than did SWR-altered saturated hydraulic conductivity. In fact, it was determined that sorptivity was the major component of three-dimensional cumulative infiltration for short and intermediate times. However, a simple one-dimensional infiltration test proved to be a fast and robust method to determine sorptivity for both untreated and treated sand. Overall, the model provided insight into the nature of sorptivity and its response to SWR. Ultimately, sorptivity is the quantitative link between SWR and infiltration.

Keywords

contact angle; infiltration; post-fire hydrology; runoff; soil water-repellency; sorptivity

Disciplines

Hydrology | Other Physics | Physics | Soil Science

File Format

pdf

File Size

1.2 MB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/


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