The effectiveness of green infrastructure at improving water quality: A literature review

Background/Question/Methods

Runoff from impervious surfaces threatens the health of aquatic systems and frequently overwhelms traditional stormwater management systems. As a consequence, developing strategies to improve stormwater management is essential for the protection of aquatic and riparian communities. We conducted a review of existing literature to determine the effectiveness of green infrastructure at reducing runoff volumes, peak flows, and pollutant loads. We compared the ability of seven types of infrastructure—buffers, detention basins, filtration devices, infiltration, constructed wetlands, green roofs, and permeable pavement—to remove total suspended solids (TSS) and total nitrogen (TN) from storm runoff. To understand the sources of variability in effectiveness, we explored the relationship between infrastructure performance and some potentially important independent variables such as climate, influent concentration, and scale.

Results/Conclusions

In general, all infrastructure studied improved runoff quality and/or quantity at a local scale. However, the high degree of variability between studies made it difficult to identify the most effective infrastructure. Pollution removal performance was not strongly related to influent concentration across studies, but may be influenced by temperature. Site-specific and watershed-level stormwater goals are recommended over strict mandates requiring the use of a specific type of green infrastructure. We conclude with insight into the potential benefits of widespread adoption of green infrastructure on aquatic and riparian ecosystems.