A landmark agreement between the New York State Dept. of Environmental Conservation and the New York City Dept. of Environmental Protection has green-lighted $3.8 billion in funding over the next 18 years to address combined-sewer overflows, or CSOs. The agreement, made in response to a consent order between the DEC and the DEP, includes $1.4 billion in gray infrastructure projects to improve the performance of the city's collection system and $2.4 billion for green infrastructure design, such as porous pavements, green streets, green and blue roofs, swales and street trees for capturing and absorbing stormwater before it enters the combined-sewer system.

According to the New York Riverkeeper, more than 27 billion gallons of raw sewage and polluted stormwater discharge from 460 CSOs into New York Harbor each year. In July 2011, an engine-room fire knocked pumps offline at the North River wastewater treatment plant; operators diverted about 20 million gallons of raw effluent into the Hudson.

"CSOs are the most significant challenge to the city in terms of overall New York Harbor water quality," says Farrell Sklerov, DEP director of communications. "Green infrastructure designs are not only cost-effective and efficient stormwater management solutions, but also bring a host of tangential benefits to local neighborhoods."

A major breakthrough, the agreement represents a comprehensive and thoughtful approach to controlling stormwater, says Dan Hendrick, New York League of Conservation Voters communications director. "Green infrastructure helps restore the natural hydrology of the landscape, promoting higher infiltration and reducing runoff," he says.

In connection with the agreement, the DEP has issued a RFP for engineering and design services contracts to develop green-infrastructure master plans in three of the city's combined-sewer areas. "We want engineering and design firms to submit bids so that we can identify green infrastructure projects, including the specific location for implementation and the most effective type of installation for each location," Sklerov says.

The DEP also is working with other city agencies to create additional plans for building green infrastructure in other CSO areas of New York. The DEP expects to award the first RFP response contracts by the summer, with design work to start immediately after.