In Brooklyn, the New York City Department of Environmental Protection is deploying a green stormwater management solution to prevent pollution of Newtown Creek. Through the use of natural systems, the solution would protect local water quality while adding more green space to the urban environment.
The Goal
The stormwater management system will take advantage of soil and vegetation to naturally filter the water that may runoff. This occurs when the city’s sewer system is forced to deal with heavy rainstorms and flooding which causes overflows. If the sewage escaping the stormwater system is left untreated, it could significantly harm the local environment the creek.
The all-natural filtration solution would help the city treat the overflow of potentially hazardous sewage at a low cost with minimal maintenance. The soil and vegetation strip would intercept sewage overflow near the curb of the street and retain the liquid until it is naturally filtered through and then released into the sewer systems.
All Shapes and Colors
According to the New York Department of Environmental Conservation, there are a variety of green stormwater management tools cities can implement that offer sustainable solutions to common problems. These management tools slow down the flow of water into sewer systems during a high influx by creating a slow-moving filtration barrier. Because they are composed of soil and vegetation, adding such infrastructure to an urban area is an easy way to beautify a neighborhood.
The NYC Department of Environmental Conservation’s stormwater management manual breaks the tools down into a few common categories including:
- Rain gardens: Filter runoff of small volumes of stormwater through soil and vegetation planted in a shallow depression.
- Bioretention areas: Larger than a rain garden, bioretention areas collect and slowly filter stormwater through soil and vegetation, and use an underdrain to release the treated water into the drain system.
- Vegetated swales or dry swales: In replace of underground storm sewers, these natural drainage paths force water to move slowly through vegetation, eliminate some discharge and provide infiltration.
- Green roofs: A planted garden on the roofs of buildings that collect stormwater and enable evaporation and evapotranspiration to reduce discharge and runoff water levels.
- Porous pavement: Stormwater is able to filtrate through holes in the surface of the pavement and enter the soil to prevent runoff of discharge and pollutants.
- Stream buffer restorations: Adding vegetation along the side of natural water paths improves water quality with additional filtration as well as green up any given area.
Along with those best practices, the U.S. Environmental Protection Agency has an extensive list of stormwater management solutions adaptive for most urban environments. Cities can add green patches to parking lots near areas of common flooding, or install rain barrels and cisterns to harvest rainwater for reuse. The water can be collected and used for irrigation elsewhere in the city. This also eliminates more unwanted runoff from entering local bodies of water and sewer systems.
In climates where certain vegetation may be difficult to maintain, there are sand and organic filters available that, like soil, force the water to be filtered through so dangerous metals, toxins and pollutants are extracted naturally. Soil amendments can also beef up filtration success by changing physical, chemical and biological characteristics so water quality is consistently maintained.
Purposefully Green
Gov1 has reported on the use of wastewater to support urban farming projects as well as allocating federal grant money to support water and sewer updates.