NEW YORK — The New York State Department of Environmental Conservation (DEC) and the New York City Department of Environmental Protection (DEP) reached a draft agreement to reduce combined sewer overflows (CSO) into area water bodies. The agreement modifies New York City’s approach to improving harbor water quality, under which the city will invest an estimated $187 million in green infrastructure projects by 2015, part of a planned $2.4 billion public and private investment over the next 20 years. The city will also complete work on approximately $1.6 billion in gray infrastructure projects.
“The draft agreement we reached with DEP proposes an adaptive, integrated and green approach to improve the water quality in the New York City area through both green and gray infrastructure projects,” DEC Commissioner Joe Martens said. “DEP’s proposal to integrate green infrastructure in the city landscape to manage stormwater and reduce combined sewer overflows in New York Harbor could serve as a model for other communities. I look forward to hearing the public’s comments on this innovative approach.”
“New York City has been using green infrastructure to improve harbor water quality on a small scale basis,” said New York City Environmental Protection Commissioner Carter Strickland. “New York Harbor is already cleaner and healthier than it has been in more than a century, but our efforts are not nearly done. When Mayor Bloomberg unveiled the NYC Green Infrastructure Plan last September, we knew that there was a more efficient and cost-effective way to significantly cut combined sewer overflows. Now, with this proposed agreement, we have laid the groundwork for one of the largest green infrastructure programs in the country. With better water quality, more trees and green roofs, and less energy intensive capture methods, this plan will maximize water quality, sustainability, and affordability for New Yorkers.”
Under the agreement, DEP will use green infrastructure to significantly reduce amounts of stormwater from entering the city’s combined sewer system from 10 percent of available impervious surfaces in combined sewer drainage areas by 2030. Milestones to reach this requirement include managing 1.5 percent of available impervious surfaces by 2015, 4 percent by 2020, 7 percent by 2025 and 10 percent by 2030.
Under this new agreement, DEP estimates it will invest $187 million in green infrastructure toward achieving the first milestone scheduled for 2015. If the city misses this milestone, it must submit a contingency plan to implement more green or gray infrastructure. If the city implements an approved contingency plan and still does not meet the milestones, it must pay a penalty. The city estimates it will require a total of $2.4 billion in both public and private investments in green infrastructure projects to meet the terms of the consent order over the next 20 years. The draft agreement also requires DEP to establish detailed Long-Term Control Plans between 2013 and 2017 to effectively address any remaining concerns with CSOs.
Under the agreement, the city will pay an additional $5.15 million for Environmental Benefit Projects including:
•$2 million to build and monitor green infrastructure demonstration projects in the Newtown Creek and Bronx River drainage basins to determine if the green projects are successful;
•$3 million for the city’s existing grant fund to perform green infrastructure projects on private property. In 2011, the program received more than 30 applications and awarded $3.8 million in grants; and
•up to $150,000 for water quality sampling in the Hutchinson River.
Under the draft agreement, DEP will continue to build $1.6 billion in other traditional gray infrastructure projects to reduce combined sewer overflows. In addition, the city will pay DEC a $200,000 penalty while an additional $1 million penalty is suspended contingent upon the city meeting a future milestone for completing a project to improve performance of the Jamaica Bay wastewater treatment plant.
To allow time to determine if green infrastructure projects can serve as effective alternatives to large-scale gray infrastructure facilities, the proposal defers making a decision to move forward with CSO tunnels for Newtown Creek and Flushing Bay until 2017, which are estimated to cost approximately $1 billion each. The draft agreement achieves $1.4 billion in cost savings for gray infrastructure projects through more efficient gray projects.
Green infrastructure improves harbor water quality by capturing and holding stormwater runoff before it enters the sewer system and contributes to CSOs. New York City, like other older urban centers, is largely serviced by a combined sewer system where stormwater and wastewater are carried through a single pipe. During heavy storms, the system can exceed its capacity, and must discharge a mix of stormwater and wastewater—called combined sewer overflow or CSO—into New York Harbor.
In addition, green infrastructure can be cost-effective and provide immediate benefits such as improving air quality and shading and cooling the city. Examples of green infrastructure projects include:
•blue roofs and green roofs, which use mechanical devices or vegetation to slow roof water from draining too quickly and overwhelming storm sewers;
•porous pavement for parking lots that allows water to seep through and be absorbed into the ground rather than running-off into the sewer system;
•tree pits and streetside swales for roadways that allow water to pool in underground holding areas until it can dissipate in the ground or transpire through plants;
•wetlands and swales for parks;
•rain barrels in some residential areas; and
•a compilation of these techniques for high-density residential housing.
The proposal takes an adaptive management approach that allows DEP to propose alternative ways to meet its required green infrastructure performance targets and to make up for missed targets, by changing its investment and design and construction strategy to reflect current conditions and up-to-date information.