By Kim Robson:
When Hurricane Sandy hit New York City in 2012, the city’s infrastructure was overwhelmed with polluted water, causing catastrophic flooding, especially in the subways. The Metropolitan Transportation Authority called the storm’s destruction the worst disaster in the 108-year history of the subway system.
In one of the most ambitious programs of its kind in the United States, New York City has quietly embarked on a 20-year, $2.4 billion project designed to protect local waterways, relying largely on “curbside gardens” that capture and retain storm water runoff. That the gardens are beautiful is effectively considered icing on the cake.
About 250 gardens planted with flowers, grasses and small trees already have appeared along corridors like this one in the Bronx, Brooklyn and Queens in the past few months. The gardens cost approximately $20,000 to $25,000 apiece, and typically are built into sidewalks, with curb cuts that let storm water flow among the shrub roses and black-eyed Susans.
Over the coming years, the Department of Environmental Protection (DEP) will expand the Green Infrastructure Program, initiated by Mayor Bloomberg, to over 2,000 curbside gardens. When the project is completed, the gardens will have the ability to collect and absorb more than four million gallons of storm water every time it rains. Softening the impervious asphalt and concrete urban landscape helps the soil naturally absorb rainwater that otherwise would funnel into the combined sewer system. When complete, the city hopes to capture more than 200 million gallons of storm water each year.
Also called bioswales, the gardens will help improve the health of the rivers and bays surrounding the city. During heavy rains, storm water can exceed the capacity of the city’s sewage treatment plants. Water quality is harmed when overflows are discharged into local waterways like the Gowanus Canal, Flushing Bay, or Newtown Creek to avoid flooding the sewage plants.
In addition to making the boroughs more resilient to extreme flooding, some of these neighborhoods have a dearth of green spaces and high rates of asthma among young people. The addition of tree canopies and vegetation will help to improve air quality, provide shade during hot summer months, and beautify otherwise ugly neighborhoods.
The DEP says the bioswales are first excavated to a depth of five feet and then backfilled with layers of stone and engineered soil that can store and manage between 1,300 and 3,000 gallons each during a storm. DEP provides funding to the Department of Parks and Recreation for maintenance crews to visit each garden weekly for upkeep, trash removal and pruning.
The New York Times says similar gardens have proven effective in other cities, most notably Philadelphia, according to advocates and researchers. WATCH one of the gardens in action during a rainfall.
Toyota of El Cajon in San Diego County recently renovated a former Home Depot site to be their new “green” flagship store. The dealership boasts scores of nifty eco-friendly features, winning it a coveted Leadership in Energy and Environmental Design (LEED) certification. One of those practical features includes extensive rain gardens, and native rock and vegetation bioswales that treat 100 percent of parking lot and roof storm water runoff, and remove 95 percent of pollutants. Even their car wash recycles the water it uses and stores the reclaimed water in holding tanks. That reclaimed water flows through an efficient landscape drip irrigation system.
Global warming is already presenting serious challenges to humans, and it will continue to do so. Working with nature instead of against her is the only hope we have for our grandchildren’s future. Planting gardens instead of paving more parking lots is just one good step.