How To Equitably Distribute Green Infrastructure

According to an article by Shaun McGillis, “In cities across the US, roads, rooftops, parking lots, sidewalks and driveways increased by an average of 326,000 hectares per year between 2012 and 2017.” These impermeable surfaces raise flood risks, but “The introduction of green infrastructures (GI), such as bioswales with permeable surfaces, has provided municipalities with a new tool to manage flood risk associated with rainfall.”

A new study from Portland State University analyzed the distribution of GI in three cities to evaluate whether it is distributed equitably.

According to the paper's lead author, Arun Pallathadka, a Ph.D. student in the Earth, Environment and Society program at Portland State, the research team found that the placement of GI in each of the cities inconsistently overlapped with areas prone to rainwater flooding, and non-white and low-income populations were more vulnerable to flood risk. Portland and Phoenix have increased investments in GI in neighborhoods with higher populations of non-white and low-income residents, marking a transition to more equitable flood risk management. In Atlanta, the risk of rainwater flooding was relatively low for non-white and low-income residents, though there was a substantial disparity in GI coverage.

As McGillis writes, “The methods deployed by the team provide cities with a novel approach to assessing the need for GI in neighborhoods prone to flooding associated with rainwater while also planning for the equitable distribution of those resources as they move ahead under the threat of increasing extreme precipitation events associated with a warming planet.”