Mapping the link between outdoor water footprint and social vulnerability in Metro Phoenix, AZ (USA)

Abstract

Outdoor surface water inequities are the disproportionate distribution of outdoor water for the management of blue and green space, including residential swimming pools and irrigated gardens, and contribute to thermal inequities that are particularly pervasive in arid climates. The purpose of this study was to map and assess social vulnerability to green space and blue space within two transects in metro Phoenix, Arizona, a socioeconomically diverse city that is water vulnerable and experiences intense urban heating. The objectives were to (1) map distribution of residential swimming pools; (2) link blueness and greenness of communities to social vulnerability; (3) evaluate the blueness and greenness of formerly redlined neighborhoods by the Home Owners’ Loan Corporation (HOLC); and (4) assess the severity of the urban heat island effect in redlined neighborhoods. The results show a strong relationship between social vulnerability and pool count and area, and overall greenness and blueness. Redlined neighborhoods have fewer pools, surface water features, and vegetation and, as a result, exhibit a greater severity of urban heat island effect than those graded as “safe”. In many cities like Phoenix, the legacy of segregative housing policies and the widening gap in socioeconomic vulnerability has amplified the disparate distribution and access to green and blue urbanscapes.