New York State and city officials announced Tuesday that they had wrapped up an agreement under which the city would commit more than $2 billion in public and private investment to new environmental techniques to help prevent the flow of untreated sewage and storm water into city waterways when it rains.

Sewer overflows are the biggest water quality problem in the New York metropolitan region, preventing many waterways from meeting federal standards for fishing, swimming and healthy habitats for wildlife. The city’s plan, announced in the fall of 2010, envisions using vegetation, soils and environmental infrastructure like porous pavement to help retain storm water before it reaches the sewer system and overloads it.

The approach is already being used in some other cities that, like New York, have a combined sewer system where storm water and sewage are carried through a single pipe. Such techniques reflect a shift away from traditional sewage-control methods like underground storage tanks. The federal Environmental Protection Agency promotes these forms of infrastructure as a cost-effective and environmentally preferable alternative.

The agreement between New York City and the state, announced at a news conference at a building at the Brooklyn Navy Yard where a rooftop farm is planned, marks the first time the state has allowed the city to use environmental infrastructure to meet federal water quality standards.



“This is a historic moment in solving water pollution in New York City,” said

Larry Levine, a senior lawyer with the Natural Resources Defense Council, one of the environmental groups advocating for the new approach. “What this does is codify 20 years of obligations to implement green infrastructure.”

To advance the plan, the city’s Department of Environmental Protection started soliciting proposals this week for $12 million in contracts to design infrastructure for areas near Flushing Bay, Newtown Creek and the Gowanus Canal. Both the Gowanus and Newtown Creek are highly contaminated sites facing federal Superfund cleanups.

In all, the city plans to invest about $187 million over the next three years and an estimated $2.4 billion of public and private financing over the next 18 years to install the green improvements, including porous pavement, green roofs and bioswales, or vegetated tree pits that help storm water runoff seep into the ground.

City officials say that with the adoption of green infrastructure, about 1.5 billion gallons of sewer overflows will be removed annually from waterways by 2030. About 12 billion gallons will be kept out of waterways through traditional and green methods combined, they add.

To provide an extra layer of accountability, environmental groups said, city and state officials agreed to insert language in the city’s federal Clean Water Act permits that will allow citizen groups to go to court to enforce the agreement if current or future government administrations violate its terms.