THE RELATIONSHIP BETWEEN HISTORIC REDLINING AND URBAN HEAT ISLAND EXPOSURE IN HARRISBURG, PENNSYLVANIA.
Type of Presentation
Presentation
Type of Project
Project I/II
Presenter 1 Program
ENVS
Presenter 1 Location
Harrisburg
Project Description
Nationwide, urban residents experience disproportionately higher levels of heat intensity due to a higher proportion of built environments to natural landscaping as compared to suburban and rural areas. Several studies have suggested that this urban heat island effect is not equitably distributed across cities as a legacy of past redlining policies, with low-income residents of color at a higher risk of experiencing heat-related illness and stress. This research aims to examine the relationship between the historic Home Owners’ Loan Corporation (HOLC) zoning districts within the City of Harrisburg and Surface Urban Heat Index values. To accomplish this, digitized HOLC zoning districts from 1935 to 1936 were overlaid on a surface heat map generated using Landsat imagery. Surface heat values were then sampled across each district using 100 randomly generated points stratified by zone and analyzed using a single-factor ANOVA. Since tree canopy cover plays a large role in mitigating land surface heat via evapotranspiration, the percent canopy cover within each zone was calculated. Residents living in areas historically zoned as desirable were significantly (df = 3, p<0.01) cooler than areas historically zoned as static, declining, or hazardous. While static and declining zones had canopy coverage similar to that of the city overall, the desirable zones had significantly higher proportions of canopy cover and hazardous zones has significantly lower proportions of canopy coverage than expected. To further inform policy efforts, this research identified areas such as vacant lots and unimproved greenspace that can be prioritized for revitalization.
Faculty Member
Christine Proctor
THE RELATIONSHIP BETWEEN HISTORIC REDLINING AND URBAN HEAT ISLAND EXPOSURE IN HARRISBURG, PENNSYLVANIA.
Nationwide, urban residents experience disproportionately higher levels of heat intensity due to a higher proportion of built environments to natural landscaping as compared to suburban and rural areas. Several studies have suggested that this urban heat island effect is not equitably distributed across cities as a legacy of past redlining policies, with low-income residents of color at a higher risk of experiencing heat-related illness and stress. This research aims to examine the relationship between the historic Home Owners’ Loan Corporation (HOLC) zoning districts within the City of Harrisburg and Surface Urban Heat Index values. To accomplish this, digitized HOLC zoning districts from 1935 to 1936 were overlaid on a surface heat map generated using Landsat imagery. Surface heat values were then sampled across each district using 100 randomly generated points stratified by zone and analyzed using a single-factor ANOVA. Since tree canopy cover plays a large role in mitigating land surface heat via evapotranspiration, the percent canopy cover within each zone was calculated. Residents living in areas historically zoned as desirable were significantly (df = 3, p<0.01) cooler than areas historically zoned as static, declining, or hazardous. While static and declining zones had canopy coverage similar to that of the city overall, the desirable zones had significantly higher proportions of canopy cover and hazardous zones has significantly lower proportions of canopy coverage than expected. To further inform policy efforts, this research identified areas such as vacant lots and unimproved greenspace that can be prioritized for revitalization.