Under the California Coastal Act, development is required to be sited and designed to minimize risks to life and property. Hazards in the Coastal Zone include geologic (i.e., seismic, tsunami, landslides), coastal bluff erosion and slope failure, beach erosion, wave impacts, flooding, and fire. This chapter includes policies to address these hazards.
Santa Barbara’s coastal bluffs and beaches are subject to coastal bluff erosion and slope failures, beach erosion, wave impacts, and coastal flooding that will substantially increase in the coming years due to the effects of sea level rise. Currently there are many existing homes, park and waterfront structures, and businesses along our shoreline that are important to our community.
Slope and shoreline protection devices (retaining walls, gunite, sea walls, rock revetments, etc.) can effectively mitigate slope instability and wave damage in the immediate vicinity of a protection device. However, erosion continues to occur around these protection devices and they weaken over time, often failing during large storm events. These devices also prevent the coastal bluffs and shoreline behind the beach from naturally eroding, which reduces sand supplies and beach widths. Seawalls and rock revetments, in particular, can substantially increase erosion of beach sand and impede the ability for the public to walk on the beach. In order to preserve the scenic and walkable nature of our beaches and coastal bluffs, the City’s Coastal LUP has always limited the use of slope and shoreline protection devices.
Additionally, the City’s Coastal LUP has always required new development to be setback from the shoreline, however, the new Draft Coastal LUP contains clearer development standards that generally document interpretations and procedures the City and the State already uses. The plan identifies locations of beaches, bluff faces, bluff edges, potential bluff erosion and slope failure areas, potential beach erosion areas, and potential inland coastal flooding areas. Policies then provide direction on technical studies required, allowed uses, and development standards in these shoreline hazard areas. The Draft Coastal LUP also addresses redevelopment and situations where minimum required buffers and other development standards cannot be met on severely constrained lots.
The benefits of clarifying bluff and shoreline development standards in the Draft Coastal LUP are that everyone (planners, property owners, City decision makers, California Coastal Commission, and the public) knows what to expect, there is more consistency in permitting development, and processing times and permit appeals can be reduced.
The Draft Coastal LUP includes a shoreline hazards screening map which depicts areas potentially subject to beach erosion, coastal bluff erosion and slope failures, wave impacts, and coastal flooding through 2100. The maps are used to identify when technical studies may be needed and certain development standards may apply. The maps are based upon studies previously adopted by the City as part of the 2011 General Plan, additional sea level rise data developed by the United States Geologic Survey (called CoSMoS 3.0), and flood maps provided by the Federal Emergency Management Agency.
Sea level rise is occurring now and will continue to increase in the future. The physical risks to Santa Barbara's Coastal Zone include shoreline erosion and degradation, narrowing of beach widths, amplified storm surges, and inundation of coatal flood waters. As part of a separate work effort, the City is developing a Sea Level Rise Adaptation Plan in the next two years that will take a detailed look at the City’s vulnerabilities and possible actions to prepare for and adapt to the impacts of sea level rise. The Draft Coastal LUP includes interim policies that consider the potential for increased shoreline hazards due to sea level rise until the Sea Level Rise Adaptation Plan is complete. This includes use of sea level rise data from a model developed by the United States Geologic Survey (called CoSMoS 3.0) in the shoreline hazard screening map. The CoSMoS model is probabilistic, meaning that it shows probable scenarios for sea level rise (as opposed to showing just worst case scenarios).