Evaluating Five Years of Soil Hydrologic Response Following the 2009 Lockheed Fire in the Coastal Santa Cruz Mountains of California

<p>The Lockheed Fire burned 31 km² (7,660 acres) of the Scotts Creek watershed in August 2009. 4.5 km² (1,100 acres) of California Polytechnic State University’s educational and research facility at Swanton Pacific Ranch. The burned region presented an opportunity for studying the hydrologic response of burned soils in the Santa Cruz Mountains where there is insufficient post-fire studies regarding fire-effects on watershed processes such as infiltration and near-surface runoff. Soil infiltration and soil water repellency were evaluated with rainfall simulations, Mini-disk Infiltrometer (MDI) and water drop penetration time tests (WDPT) at sites represented by variations in burn severity, soils, and vegetation types throughout the Scotts Creek watershed each year for 5 years following the burn. Mixed-effects modeling was utilized on the 3 datasets to evaluate if changes could be detected in infiltration rates and water repellency following the fire. Rainfall simulations and WDPT tests showed that the fire did not have a statistically-significant impact on infiltration rates or soil water repellency, whereas the MDI tests detected a statistically-significant impact on post-fire infiltration. While the MDI results showed that fire had a significant impact on the hydrologic response over time, questions arose regarding challenges associated with sampling suggesting the method may not be pursued on steep slopes with high surface rock fragments or in the presence of large soil macropores. It is recognized that additional understanding would be gained from having multiple replications at each site every year and tests could be conducted on a subwatershed scale to account for the naturally occurring variability of larger watersheds.</p>

Name thesis:degree_name

MS in Forestry Sciences

Discipline thesis:degree_discipline

Natural Resources Management

Year dc:date.available

2014

Author dc:creator

• Crable, Mary Theresa

Contributors dc:contributor

• Brian Dietterick
• College of Agriculture, Food, and Environmental Sciences

• near-surface runoff
• soil water repellency
• infiltration
• rainfall simulation
• Mini-disk Infiltometer
• hydrologic response
• Forest Management
• Other Forestry and Forest Sciences

Identifier

10.15368/theses.2014.191

OAI identifier oai:identifier

oai:digitalcommons.calpoly.edu:theses-2443