The Environmental and Ecological Benefits of Green Infrastructure for Stormwater Runoff in Urban Areas

Water runoff from impervious surfaces threatens urban ecosystems, public health and property values. Traditional stormwater management systems are often overwhelmed after big storms, prompting the evaluation of alternative green infrastructure (GI) strategies to improve stormwater management. Here, we present a synthesis to determine the effectiveness of GI— detention basins, filtration devices, bioinfiltration, constructed wetlands, green roofs, and permeable pavement—in reducing runoff volumes and peak flows and in mitigating water pollutant loads by testing and using surrogates such as total suspended solids (TSS) and total nitrogen (TN) from storm runoff. In general, all infrastructures reduced stormwater quantity and/or improved runoff water quality at a local scale, and their performance was comparable to more traditional stormwater management approaches (i.e. detention basins). There was a general agreement between the peer-reviewed data and the best management practice (BMP) database for most GI effectiveness, particularly with respect to water quality. Our analysis shows, however, that the effectiveness of most GI was highly variable, possibly due to climate, influent concentration, or scale. Despite the variability in stormwater runoff performance, most GI can potentially provide valuable habitat for wildlife in urban settings. GI can be designed to promote additional ecosystem services in urban areas, such as habitat for flora or pollinators that can aid in urban gardens or C sequestration, among many others.