Finding Balance in Our Urbanized Watersheds - Policy Recommendations for Alternative Emergency Debris Management Actions in Santa Barbara County

Record precipitation events in Santa Barbara County have increased the need for flood control strategies that mitigate immediate dangers to the public. Debris basins have been an ongoing strategy to combat flood risk. These structures are designed to capture sediment at the mouths of canyons to prevent floods downstream. By capturing sediment at the canyon mouth, debris basins reduce the potential for flow impediments at lower reaches. During high-flow events, Santa Barbara County debris management actions are guided by emergency permits. These permits are designed to streamline removal and relocation of sediment that threatens life or property near flood-prone channels. There is growing concern about the physicochemical effects of this practice, especially as extreme weather warrants more frequent use of emergency permits. A significant component of debris basin management is sediment relocation. Historically, Goleta Beach and Carpinteria Beach have been designated as receiving sites for sediment from upstream debris basins during emergency situations. While this practice may have the potential to protect coastlines from erosion, the long-term effects on coastal ecosystems are uncertain. Our team will analyze the differences between routine and emergency permit actions, and the resulting effects on the San Ysidro Creek ecology and physical system. Overall, the project will provide a framework for coastal stream sediment management, using San Ysidro Creek as a model to guide future projects.