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- EPA’s Involvement at this Site
- What is the current site status?
- What's being done to protect human health and the environment?
EPA’s Involvement at this Site
The EPA added the Gowanus Canal to the Superfund program’s National Priorities List on March 2, 2010.
Based upon the results of an extensive investigation of the contamination in the Canal and public comment on a proposed remedy, in September 2013, the EPA finalized a plan to clean up the contaminated sediment that has accumulated as a result of industrial and sewer discharges. The plan divides the canal into three segments. The first segment runs from the top of the Canal to 3rd Street, the second segment from 3rd Street to just south of the Hamilton Avenue Bridge and the third segment runs from the Hamilton Avenue Bridge to the mouth of the Canal. Approximately 300,000 cubic yards of highly-contaminated sediment will be dredged from the first and second segments. For the third segment, approximately 281,000 cubic yards of contaminated sediment will be dredged. The plan also calls for removing contaminated material that was placed in the 1st Street turning basin decades ago and restoring about 475 feet of the former basin. A portion of the 5th Street turning basin underneath the 3rd Avenue bridge and extending about 25 feet to the east of the bridge will be dredged and restored.
In dredged areas of the Canal where contamination exists in the native sediment, multiple layers of clean material will placed. The multilayer cap will consist of an “active” layer made of a specific type of clay that will remove contamination that could well up from below, an “isolation” layer of sand and gravel that will ensure that the contaminants are not exposed, and an “armor” layer of heavier gravel and stone to prevent erosion of the underlying layers from boat traffic and canal currents. Finally, sufficient clean sand will be placed on top of the “armor” layer to fill in the voids between the stones and to establish sufficient depth in order to restore the canal bottom as a habitat. In the middle and upper segments of the Canal where the native sediment is contaminated with coal tar, the sediment will be stabilized by mixing it with concrete or similar materials. The stabilized areas will then be covered with the multiple layer cap as described above.
The remedy also includes the construction of retention tanks to reduce the volume of contaminated sewage solid discharges from the combined sewer overflows at two major outfalls in the upper portion of the canal be outfitted with retention tanks.
The cost of the cleanup plan is estimated to be $500 million.
What is the current site status?
National Grid, New York City and other potentially responsible parties (PRPs) are currently preparing the design of the selected remedy. It is anticipated that the design related to the upper portion of the Canal will be completed in 2017.
What's being done to protect human health and the environment?
The Gowanus Canal has been heavily contaminated throughout its existence. No environmental remediation has been undertaken, to date. Remedial efforts are currently underway at three former MGPs along the Canal. These plants are believed to be sources of much of the PAH contamination in the Canal – the former Fulton MGP site, the former Citizens Gas Works MGP site and former Metropolitan Gas Light Company MGP site. National Grid is the PRP for the former MGP sites.
In April 2009, the EPA proposed putting the Gowanus Canal on the National Priorities List. While the community and many elected officials supported the listing, New York City and some development interests did not. New York City proposed an alternate approach that would have depended heavily on the assumption of long-term Congressional funding to the U.S. Army Corps of Engineers (COE). After consulting extensively with the many stakeholders who expressed interest in the future of the Gowanus Canal and the surrounding area, the EPA determined that Superfund designation was the best path to the cleanup of this heavily contaminated and long-neglected urban waterway. The EPA placed the site on the National Priorities List on March 4, 2010.
The EPA, in conjunction with New York City and National Grid, performed supplemental field work to characterize the nature and extent of contamination in the canal; determine the human health and ecological risks from exposure to contamination in the canal; identify the sources of contamination to the Canal, including ongoing sources of contamination that need to be addressed so that a sustainable remedy can be developed and implemented; and determine the physical and chemical characteristics of the canal that will influence the development, evaluation and selection of cleanup alternatives. This work, which supplemented previous studies carried out by the COE and National Grid, included a bathymetric (underwater depth) study, sediment sampling, monitoring well installation, groundwater, surface water, air, sediment and fish tissue sampling, sewer system sampling, and an investigation of hundreds of pipes that lead to the canal. A remedial investigation report was released to the public on February 2, 2011 and a public meeting was held on February 23, 2011 to discuss the results of the study. A feasibility study which developed and evaluated remedial alternatives for mitigating human and ecological risks in the Canal was released the public on December 30, 2011, followed by an informational public meeting held on January 24, 2012. Nearly 200 people were in attendance.
On December 27, 2012, the EPA released a Proposed Plan describing its proposed remedy for the site. The Proposed Plan recommended removing all of the contaminated sediment that has accumulated as a result of industrial and sewer discharges from the bottom of the canal by dredging. The dredged areas would then be capped. The EPA also recommended controls to prevent combined sewer overflows and other land-based sources of contamination from compromising the cleanup. On January 23, 2013, and January 24, 2013, the EPA held public meetings to present the Proposed Plan, including the preferred remedy, and respond to questions and comments from the 200 attendees at the first meeting and 100 attendees at the second meeting. A Record of Decision, selecting a remedy for the site, was signed on September 27, 2013.
Following the selection of the remedy for the site, the EPA issued orders to National Grid, New York City and other PRPs to design the selected remedy. It is anticipated that the design for the upper portion of the Canal will be completed in 2017.