Green Infrastructure (GI) describes a set of design interventions to better modulate stormwater runoff in cities with high levels of impervious surfaces. These designs include rain gardens, planter boxes, bioswales, urban gardens, and green roofs. These interventions are particularly exigent in cities that experience combined sewer overflow (CSO): when gray infrastructure channels both storm water and waste water in the same system, which in heavy rain events can exceed volume capacities and release untreated sewage into waterways. Several types of GI use biomimicry to reduce storm water volumes by taking advantage of the natural ability of trees and green plantings to slow stormwater flows and absorb rainwater, then release gradually in transpiration. Well-planned GI can also support co-benefits to communities by decreasing the urban heat island effect, improving air and water quality, providing urban wildlife habitat, and enhancing aesthetics in community spaces. Research by Hopkins et al. (2018) examines the considerable growth in city planning and installation of GI following a 2007 U.S. Environmental Protection Agency (EPA) memorandum supporting GI policy and funding, coupled with EPA consent decrees that require cities to remediate their CSO problems. However, research by Hoover et al. (2021) reveals how environmental justice (EJ) considerations are rarely built into city plans for siting GI. This lesson challenges learners to integrate GI hydrology, public policy, and EJ co-benefits.
Green Roofs, Living Walls, and Green Infastructure Read More
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