Measuring climate resilience in the built environment around the Atlanta BeltLine

Abstract

There is a need to reorient the discourse around urban sustainability and, increasingly, urban resilience away from a reliance on intuition and appearance toward more rigorous evaluation of performance – particularly at the scale of interacting systems rather than individual sites. Large-scale, “sustainable redevelopment” projects are appropriate testing grounds for this kind of quantitative evaluation. This thesis looks at the Atlanta BeltLine, a 22-mile loop of repurposed rail corridor encircling the urban core of Atlanta, as a case study for measuring progress toward urban climate resilience objectives at the district scale. Specifically, it considers Subarea 5 of the BeltLine Planning Area between 2009 and 2017 in order to compare conditions before and after construction of the project’s first flagship trail and a 17-acre park. Findings suggest that the study area experienced a small net loss of tree canopy coverage (-3.3%) and small net gain in impervious surfaces (+2.4%) despite the addition of BeltLine green infrastructure. At the same time, using a methodology based on the LEED for Neighborhood Development (LEED-ND) certification system, the author estimated that just over a quarter of the study area’s “green growth” land supply – those parcels endowed with locational characteristics conducive to more resource-efficient development patterns – had been redeveloped by 2017. The findings underscore the importance of policies that explicitly seek to protect and enhance tree canopy in neighborhoods where green infrastructure is expected to spur redevelopment. It also raises questions about reconciling potential conflicts between strategies to pursue urban climate resilience through compact “green urbanism” on one hand and “green” land cover on the other.