Green infrastructure (GI) has recently gained global momentum in direct response to governing bodies and communities targeting sustainable urban stormwater management. GI, often termed low impact development (LID) in North America, uses plants, soils, and landscape design (e.g., rain gardens, rain barrels, and bioretention areas) to retain and gradually release precipitation, snowmelt, and associated pollutants in urban and suburban areas. LID therefore helps to prevent flooding and water pollution that occurs via rapid runoff from sidewalks, parking lots, roads, and other impermeable surfaces.

Quantifying the effectiveness of LID for improving urban water quality and minimizing flooding potential has gained traction in recent years. However, most of this work is primarily focused on LID impacts across small areas of land, such as plots, parcels, or drainage areas immediate to the LID. Therefore, a key science and management question remains: How effective are LID practices for water quality and flood management at the scale of catchments, or watersheds – i.e., the scale of management?

In the WIREs Water overview article “Green Infrastructure and Its Catchment-Scale Effects: An Emerging Science”, Heather Golden at the US Environmental Protection Agency (USEPA) Office of Research and Development (ORD) and Nahal Hoghooghi, an Oak Ridge Science and Education Fellow at the USEPA/ORD and now at the University of Georgia, address how recent and future research can provide insights on the efficacy of LID practices at catchment scales.

The authors discuss the state of the science on LID implementation at catchment scales, how to scale research findings on the effectiveness of LID practices to catchments, and how modeling can be used as a tool to “scale-up” our understanding of how LID practices affect catchment-scale water quantity and quality.

Golden and Hoghooghi conclude with highlighting future research questions regarding evaluating and implementing LID practices across catchments, particularly those of mixed land cover types (e.g. urban and agriculture). They further provide recommendations for quantifying catchment-scale LID impacts using models combined with novel data. Insights from this overview can be applied globally for future catchment-scale LID management and research.

Kindly contributed by Heather Golden.