A New Way to Keep Pollution Out of Our Waterways

The drainage site beneath the Van Wyck Expressway before the HOLDS bioswale was installed, and after. Photos: dland Studio.

Pollution can flow into our waterways from many sources, but in developed areas our water bodies are especially vulnerable to stormwater runoff that pours from elevated highways, carrying with it oil, heavy metals and other contaminants into sewers or directly into rivers, streams and coastal waterways.

To tackle the problem, Regional Plan Association partnered with landscape architecture firm dland Studio to develop and construct an environmentally friendly system that could absorb and filter pollutants before the rainfall made its way into water bodies or sewers. The staff at dland built a bioswale – essentially a planter that uses vegetation and soil to absorb water – that was carefully engineered to withstand the intense flow of contaminants from highway overpasses and designed with plant matter that thrives in low-light conditions.

With support from the New York City Department of Environmental Protection and National Fish and Wildlife Foundation, two Highway Overpass Landscape Detention System basins have been installed for the past year in a pilot project near Flushing Creek in Flushing Meadows Corona Park, where they filter stormwater disgorged from the Van Wyck Expressway.The system will be monitored over the next two years to assess the basins’ effects on stormwater capture and remediation. As part of the project, RPA and dland identified 58 other potential sites along the Long Island Sound and Hudson- Raritan River Estuary shorelines where bioswale systems such as these would protect public parkland and vital water and habitats from highway runoff.

Read more about the HOLD System pilot project here and here.

--Kyle Kozar