In 2010, New York City released an ambitious green infrastructure plan to spur investment in green roofs and streets, bioswales, and other natural systems to manage stormwater. Just last month, New York State and city officials announced a broad-reaching financing agreement was reached that will commit more than $2.4 billion in public and private investment towards the plan over the next 18 years, with $187 million to be spent over the next three years, reports The New York Times’ Green blog. New York City now joins Philadelphia, Toronto, D.C., and a few other cities now making serious financial investments in applying nature to solve expensive infrastructural challenges.
Green infrastructure can help cities shore-up outdated combined stormwater and sewer systems, which tend to overflow in heavy storm events. In heavy rain, sewage overwhelms these systems and excrement enters water supplies. Because stormwater then can’t enter the drains, contaminant-laden water just sits on streets, funneling towards waterways as well. These overflows are a big problem in New York and one reason so many waterways don’t meet federal standards for fishing, swimming, and healthy habits for wildlife, writes The New York Times. With green infrastructure, water is captured onsite so it doesn’t overload those old pipe systems, which are prohibitively expensive to replace in major cities.
While the Enviromental Protection Agency (E.P.A.) has been re-evaluating its national rules on green infrastructure (and even asked for ASLA’s help in evaluating the benefits of these systems), few states have gotten behind these approaches yet. So the fact that New York State has supported New York City is a major win for using green infrastructure to meet federal water quality standards. According to the state and city, the new green infrastructure investments will eliminate 1.5 billion gallons of sewer overflow annually by 2030, while 12 billion gallons will be kept out of New York’s waterways through combined green and grey infrastructure systems, saving the state and city loads of money in the process.
A significant portion of the $187 million near-term investment will go to bioswales, targeting the areas of heavy “outfalls.” These bioswales are effectively trees set in extra-deep pits and surrounded by vegetation and low curbs to encourage water absorption. As Capital New York reports, more than 100 are in the works for 2012, using an approved “Right-of-way Bioswale” standard model settled on by the city government’s many departments. That model came out of some 20 test sites established throughout the city.
Of course, landscape architects, who will design and implement these systems, are fans. Nette Compton, ASLA, a landscape architect who runs the green infrastructure department in the NYC Parks and Recreation department, said: “I love bioswales. Bioswales are as close to a natural system as we can get on a New York City street.” Compton told Capital New York that each of the new bioswales will cost $13,000 but “costs may go down” as the city scales up the standard model.
Some of those first bioswales were put in Gowanus Canal last November. The four there now are expected to keep 7,200 gallons out of the canal, one of the worst polluted waterways in the U.S. The city also seems to be smart about tree placement and diversity in order to protect against bugs and disease. And the benefits may go beyond simply environmental value: the bioswales alone are expected to bring in $400 million in new taxes by improving property value. Still, others think the city still needs to work on the standard bioswale model, arguing that the soil volumes used just aren’t enough.
Also, check out ASLA’s animations on green infrastructure and urban forests, a resource guide, along with 450+ green infrastructure case studies, designed to provide the E.P.A. with data on the many environmental and economic benefits of these systems.
Image credit: Bioswale / NYC Environmental Protection