RAPID: Post-Fire Geomorphic Change Detection in a Small Mountainous River Estuary

University Of California-Riverside, Riverside CA

Investigators

Abstract

This project will focus on the impacts of flooding and debris flows on the landforms and physical functioning of the estuary of Scott Creek, California after wildfire. The Scott Creek watershed almost completely burned in the August, 2020 CZU Lightning Complex Fire, and in the recent past the estuary has experienced dramatic changes from direct human management and sea-level rise. Because fire has destabilized hillslopes and increased the production of runoff, Scott Creek will likely flood its estuary with water and sediment during even relatively minor storm events. Mountainous coastal regions prone to wildfire, such as those of the US Pacific Coast, are also concentrations of human lives, infrastructure and economic importance. Better understanding of the processes controlling the impacts of debris flows on coastal systems after wildfire is critical to informing effective management and restoration of these systems in the context of previous human modification and sea-level rise. The scientific advances from this project will also inform hazard management for the protection of human health and prosperity in coastal regions impacted by wildfire. This work is conducted by a research group dedicated to creating opportunities for underrepresented groups in the geosciences, which will be advanced through this project’s conduct, future analysis of resultant datasets with additional early career scientists, and incorporation of results into educational materials at the University of California, Riverside. This project will provide urgently needed, perishable data supporting a novel opportunity to investigate the impacts of wildfire on landform change in the Scott Creek watershed. Surveying and sampling will be conducted before and after each rainstorm or rainstorm cluster during the 2021 wet season. The ground surface of the estuary, both above and below standing water, will be surveyed using high resolution laser scanning and echo sounder techniques, respectively. Sediment and water samples will also be collected from locations throughout the estuary and investigated for physical and chemical characteristics that provide information about sediment source and hydrodynamic transport conditions. These data will be leveraged into a more comprehensive study of longer term (multi-year) geomorphic and ecological changes in the estuary following the fire with a focus on the processes contributing to the development of landforms and sediment deposits, and their impacts on physical and ecological function. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.