Pushed to the edges? Electivity patterns of urban stream homeless encampments in environmentally burdened areas

Urban stream corridors in the San Francisco Bay Area have increasingly become locations for homeless encampments, yet little is known about the environmental conditions of these spaces. This study uses a geospatial electivity index to examine whether urban stream encampments in Santa Clara and Contra Costa counties are disproportionately located in census tracts with high pollution burdens, as measured by CalEnviroScreen 4.0. Findings show a statistically significant overrepresentation of encampments in census tracts in the top 25% of pollution and vulnerability scores, and a significant underrepresentation in lower-pollution areas. These results suggest that homeless individuals are being pushed toward environmentally hazardous areas, likely due to enforcement pressures, lack of viable alternatives, and land use patterns that concentrate polluting infrastructure and activities in low-resource areas. The findings have implications for environmental justice, public health, and urban policy, especially as CalEnviroScreen plays a central role in allocating state resources to disadvantaged communities.