Stormwater isn’t impervious to racism: rethinking stormwater capture in Los Angeles County

Ubiquitous to the modern urban landscape, impervious surfaces like concrete and asphalt contribute to environmental harms, including stormwater runoff and urban heat island effects. Replacing impervious surface with green stormwater infrastructure can help address these harms and offer other environmental and social benefits. Existing literature has found that neighbourhoods of colour on average have more impervious surface, less urban tree canopy and experience hotter temperatures. This study builds on the literature by examining the relationship between race and impervious surface in Los Angeles County and tying results to the local stormwater context. This study (1) analyses impervious surface levels by racial group quintiles at the census tract level and (2) utilises spatial autoregressive combined (SAC) regressions with control variables for income, owner-occupied rates, population density and land use types. Results show that census tracts with more people of colour have more impervious surface, and Black and Hispanic residents experience the most impervious surface on average. For white residents, the inverse is true – census tracts with higher white populations have less impervious surface. SAC regressions show that the magnitude of the relationship between race and impervious surface diminishes with more control variables, though statistical significance remains for whites and Hispanics in the model with all controls. Results indicate that neighbourhood environments are still shaped by systemic racism. However, by targeting green stormwater infrastructure to neighbourhoods of colour, there is the potential to help reverse the legacy of environmental racism while also meeting stormwater goals.