Community Vulnerability (BCDC 2023)

The San Francisco Bay Conservation and Development Commission Adapting to Rising Tides Program developed a dataset to better understand community vulnerability to current and future flooding due to sea level rise and storm surges, and has published an update to the original dataset that now incorporates the American Community Survey 2017-2021 5-year estimates and the CalEnviroScreen 4.0 update. The past iteration of this data was used in the Adapting To Rising Tides Bay Area Sea Level Rise Vulnerability and Assessment project as well as helping inform the implementation of the BCDC Environmental Justice and Social Equity Bay Plan amendment. Data and resources can be accessed at [https://www.bcdc.ca.gov/data/community.html]. For information about data development and access please review the Community Vulnerability User Guide ([https://www.adaptingtorisingtides.org/wp-content/uploads/2024/01/CommunityVulnerability_UserGuide_BCDC_2023_Final.pdf]) and BCDC’s Github Repository ([https://github.com/BCDC-GIS/community-vulnerability]). For more information, please contact [GIS@bcdc.ca.gov]. The community vulnerability dataset contains four categories of information: 1. Social Vulnerability Indicators: Certain socioeconomic characteristics may reduce ability to prepare for, respond to, or recover from a hazard event. Census block groups with high concentrations (relative to the nine county Bay Area) of these characteristics are flagged as socially vulnerable, with each block group assigned a rank of highest, high, moderate, and low. The data has been updated to use the American Community Survey (ACS) 2021 5-year estimates but is anticipated to be updated as new ACS 5-year estimates become available; 2. Contamination Vulnerability Indicators: The presence of contaminated lands and water raises health and environmental justice concerns, which worsen with flooding and sea level rise. A rank of highest, high, moderate, and lower for the severity of contamination in each block group was calculated using data compiled by CalEPA Office of Environmental Health Hazard Assessment (OEHHA) for use in CalEnviroScreen 4.0; 3. Residential Exposure to Sea Level Rise: Calculated by joining Metropolitan Transportation Commission 2010 residential parcel data with 2017 ART Bay Area Sea Level Rise and Shoreline Analysis data, FEMA 100 and 500 year flood zone data, and San Francisco 100-year precipitation data to generate the number of residential units exposed at each water level summed by block group. This methodology assumes that once a parcel is exposed to any amount of flooding, the entire number of residential units within that parcel are considered impacted; 4. Complementary Community Vulnerability Screening Tools: Many screening approaches exist to characterize disadvantaged or vulnerable communities. Often in the Bay Area, different designations of disadvantaged/vulnerable communities are located in the same area. It is recommended to use the ART approach in combination with other complementary tools and designations. The following are included in this shapefile as fields for cross-referencing: CalEnviroScreen 4.0 total score, Metropolitan Transportation Commission Community of Concern designation, UC Berkeley Displacement and Gentrification Typologies. ***In 2023, BCDC updated the symbology and classification of vulnerability to better highlight areas with both social and contamination vulnerability in our web mapping application. This included combining the “Moderate”, “High”, and “Highest” social vulnerability categories, as well as combining the “Low” and “Not Calculated” categories. A similar simplification was done with the contamination vulnerability attributes. Where “Moderate”, “High”, or “Highest” social vulnerability overlapped with “Moderate”, “High” or “Highest” contamination vulnerability, those block groups were labeled as “Social and Contamination Vulnerable”. Where those block groups did not overlap with “Moderate”, High” or “Highest” contamination vulnerability they were simply labeled as “Social Vulnerability”. Where block groups were “Low” for both vulnerability types, they were categorized as “Low”, and where block groups were not calculated due to low population, they were categorized as “Not Calculated”. This information is the “Combined Vulnerability” attribute. ****