Spatial and Temporal Analysis of Flood Risk in Massachusetts Environmental Justice Communities

Abstract

During the past decade, changing population dynamics in Massachusetts raised concerns about inequitable exposure to floods in historically underserved communities. To examine the interplay between socioeconomic and demographic characteristics and flood risk, we constructed spatially explicit geospatial models to assess the distribution of flood risk from 2010 to 2020 across the 351 municipalities and 4,985 census block groups using the Environmental Justice Index (EJI) developed by the Massachusetts Executive Office of Energy and Environmental Affairs. EJI uses individual categorical variables to describe eight different combinations of socioeconomic and demographic characteristics, allowing for assessments through different types of models We found an increasing presence by 69.9% of EJ communities residing in flood zones during the past decade. Specific combinations of socioeconomic indicators, such as minority status linked with limited English proficiency and low-income status, exhibit a statistically significant likelihood of residing in flood zones from 2010 to 2020, relative to non-EJ. Of these socioeconomic indicators, we note a 124.4% increase by area in minority status with limited English proficiency living in flood-prone block groups (3.8 km2 in 2020), a 79.6% increase by area for those with only minority status (92 km2 in 2020), and a 522.6% increase in low-income with limited English proficiency zones by area occurring in the flood-prone block group (0.07 km2 in 2020). Our findings demonstrate that racial and ethnic composition in addition to income inequality are correlated to flood exposure in Massachusetts at both the census block group and at the municipality level. Finer scale analysis revealed additional hotspots of flooding that are obscured at the municipality level. These results not only underscore the potential for harm with increasing intensity and magnitude of flooding in EJ communities but also demonstrate the need for disaster risk reduction to center racial and EJ in flood mitigation efforts. Our study may help inform equitable decision making and equitable adaptation planning under climate change at different spatial scales.