How Cities Are Incorporating Green Infrastructure To Help With Storm Surges

November 14, 2019

As storms have become more frequent and more severe due to climate change, many cities have begun making changes to how they manage these types of incidences with green infrastructure initiatives. These initiatives are to reduce and handle the excess water that storms bring in to urban environments, and even use it to help the environment and economy.  

Why We Need Green Infrastructure

Storm runoff is a greater problem in urban areas where pavement and other non-porous surfaces prevent much of it from soaking into the ground. When rains are particularly heavy erosion and flooding can occur causing damage to property and other infrastructure. Stormwater is also a major cause of pollution. The runoff can carry trash, bacteria and other pollutants with it. Traditionally, the infrastructure to move stormwater safely in cities includes pipes for drainage and water treatment systems.  

What Is Green Infrastructure?

Green infrastructure includes a variety of  tactics to better soak up and/or store water. These could include adding more open space and vegetation such as gardens, planter boxes, green roofs, or swales (a shallow sunken channel) with plants and grasses to help absorb water. Cities can also change existing drainage to better trap and reuse water. For example, rerouting rooftop pipes from draining rainwater into the sewer to rain barrels or cisterns. Other more costly actions include adding permeable pavement that can soak up rainwater and perhaps evene  store it. This pavement can be made of pervious concrete, porous asphalt, or permeable interlocking pavers. This practice could be particularly cost effective in areas where land values are high and flooding or icing is a major problem.

Green Infrastructure in Norwalk

The recently completed Citywide Plan (POCD) recognizes the potential impacts and challenges that climate change poses. The City is beginning to discuss how to address these major challenges. The City is a registered member of Sustainable CT and will be seeking certification. In addition, the City has been considering green infrastructure incentives and requirements into its land use codes.

While we are planning for our  future, we are also implementing green infrastructure. In South Norwalk, the Webster Parking Lot will be installing green infrastructure after recent torrential rainfalls flooded nearby buildings several times, including the Bow Tie Cinema. The project envisions adding planters and other types of vegetation, including more trees, to help soak up the water in the lot before it goes into the drainage system. 

The city received an Environmental Protection Agency grant of $250,000 through the Long Island Sound Futures Fund to help finance the initiative.  The project is being run by the office of Transportation, Mobility and Parking and the Department of Public Works.   

The green infrastructure will not only help ease flooding of the Webster Lot and make it more pleasant to look at, it will also help to keep Long Island Sound clean. Given the close proximity of the lot to the Sound, adding areas to absorb the water in the lot, means fewer pollutants will run into the Sound.  Adding green infrastructure to the lot will prevent more than 6 million gallons of stormwater and 12 pounds of nitrogen from flowing into the Sound annually.