Inducement of Hydrophobicity on Laboratory Specimens to Study Wildfire Impacts on Infiltration for Revegetation and Erosion

As wildfires become increasingly more prevalent in today’s world, the need for restoration and remediation efforts grows respectively. A fire event can cause hydrophobicity within the top few inches of the soil’s surface, and this hydrophobic layer when combined with the removal of exterior stabilizers such as root systems has the potential to increase runoff by more than ten times the average rate. To rapidly repair these burned environments and preserve any surrounding systems, restoration may be needed. Remedial studies of hydrophobic soils occur in the field or the laboratory with soil samples taken from the field after real fire events. This can make the research site-specific until the overall quantities of research and analyzed data reach a broad enough range to develop empirical correlations. This research outlines a standardized procedure for inducing hydrophobic properties of soil. By standardizing the process to produce hydrophobic specimens, the collection of nonuniform samples from the field can be avoided for fundamental research—before applied field research is pursued—and the degree of soil hydrophobicity can be adjusted to evaluate a range of potential field conditions. The procedure is critical for the development of a range of consistent degrees of hydrophobicity in soil that makes laboratory testing. Once the procedure for inducement of hydrophobicity is standardized and the repeatability is established, further outside research can be conducted in a more controlled, repeatable, and methodical manner. To standardize and develop hydrophobic properties that most closely resemble field conditions, specimens of Ottawa sand with varying hydrophobic strengths are prepared by analyzing and applying wood smoke condensates. Then infiltration tests are performed on these specimens to correlate the impact of hydrophobicity on infiltration through various altered Ottawa sand specimens.