EPA Issues Administrative Order Requiring City to Construct Sewage Retention Tanks for Gowanus Canal Superfund Site Cleanup

 

EPA Issues Administrative Order Requiring City to Construct Sewage Retention Tanks for Gowanus Canal Superfund Site Cleanup

 

NEW YORK (March 30, 2021) The U.S. Environmental Protection Agency (EPA) ordered the City of New York (city) to construct and operate two Combined Sewer Overflow (CSO) retention tanks to control contaminated solids discharges at the Gowanus Canal Superfund site in Brooklyn, New York, which is a key component of the Gowanus Canal cleanup. The EPA’s order follows previous orders that EPA issued in 2014 and 2016 to require the city to find a location for and design the two tanks. Controls to reduce CSO discharges and prevent other land-based sources of pollution, such as street runoff, from compromising the cleanup are a critical part of the site’s cleanup plan.

“This order will ensure that EPA’s cleanup efforts will not be undermined by uncontrolled combined sewer overflow discharges that have contributed to the chemical contamination of this waterway and impacted this community for the past century and a half,” said EPA Acting Regional Administrator Walter Mugdan. “To ensure the integrity of the dredging work, the retention tanks will control New York City’s sewer outfalls over the long-term.”

The administrative order, issued on March 29, 2021, requires the city to construct one 8-million-gallon tank, located at the head of the canal, and one 4-million-gallon tank, located at a New York City Department of Sanitation Salt Lot near the middle of the canal.

The order also requires the city to, among other things:

• Ensure that developers comply with municipal stormwater regulations within the Gowanus area to prevent additional sewer volume from impairing the effectiveness of the CSO tanks;
• Provide treatment for separated stormwater discharges;
• Perform monitoring of sewer solids discharges to ensure protection of the dredging remedy;
• Perform associated maintenance dredging, if determined by EPA to be necessary;
• Construct a bulkhead on City-owned property to prepare for the second phase of dredging work; and
• Adhere to an overall schedule for remaining tank design work and construction.

The 2013 cleanup plan for the Gowanus Canal Superfund site includes dredging to remove contaminated sediment from the bottom of the canal, which has accumulated because of industrial activity and CSO discharges. More than a dozen contaminants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and heavy metals, including mercury, lead, and copper, are present at high levels in the Gowanus Canal sediments. Dredged sediment that contains high levels of liquid tar will be thermally treated at an off-site facility and disposed. The less contaminated dredged sediment will be processed at an off-site facility to transform it into a beneficial use product, such as landfill cover. Certain areas of the native sediment, below the original canal bottom, that contain mobile liquid tar and are too deep to excavate, will be mixed with cement and solidified to prevent the migration of the tar into the water of the canal. Following dredging and solidification of areas of the native sediment, construction of a multilayer cap in dredged areas will isolate and prevent migration of any dissolved chemicals remaining in the deep native sediments. 

Cleanup work to resume next month at Grasse River Superfund Site in Massena, New York

 

Cleanup work to resume next month at Grasse River Superfund Site in Massena, New York

ALBANY, NY (March 30, 2021) – The U.S. Environmental Protection Agency (EPA) announced today that in-river work will resume next month to address sediment contaminated with polychlorinated biphenyls (PCBs) at the Grasse River Superfund Site (aka Alcoa Aggregation) in Massena, New York.

“It’s exciting to see the tremendous progress that has been made as we near the finish line for this critically important project,” said Walter Mugdan, Acting Regional Administrator. “EPA, the New York State Department of Environmental Conservation, and the Saint Regis Mohawk Tribe continue to work together on the oversight of the various components of the project.”

In 2013, EPA selected a cleanup plan for the site that called for dredging and capping of PCB‐contaminated sediment in a 7.2‐mile stretch of river. The 2021 work will primarily include placement of a 12-inch sand, gravel and/or stone cap in the lower five miles of the main river channel from the Route 131 Bridge to the mouth of the Grasse River, covering over 200 acres; sand backfilling in areas dredged in 2020 near Snug Harbor; and habitat reconstruction throughout the site. The major elements of the in-river work are expected to be completed by the end of 2021. COVID-19 protocols will continue to be followed and safeguards will be maintained for the protection of site workers and the community.

To support this year’s work, an extended underwater pipeline will be used to transport some clean capping material from two staging areas to river locations. This operation will occur 24 hours a day, six days a week. The pipeline will be submerged along the river shoreline, with some floating sections near the cap operations. The pipeline will be marked with orange and white buoys. Designated crossing areas will be marked with green and red buoys in the channel. The remainder of the capping material will be transported by barges pushed by tugboats and placed mechanically on the river bottom using excavator-type buckets. On-river warning signs will be posted to alert oncoming boating traffic.

Information on boater safety can be found on the Arconic project website: www.thegrasseriver.com. Additional recreation advice is available from the New York State Department of Health: “Recreation Advice for Lower Grasse River During Dredging and Capping.” Recreational boaters are asked to take caution, reduce speed and adhere to traffic patterns in the project area.

A limited amount of dredging will be conducted in the navigational channel in 2021 just downstream of Snug Harbor. Snug Harbor is a small embayment (an embayment is a part of a body of water that extends beyond the general shoreline) on the north shore of the Grasse River, located about a third of a mile upstream from where it joins the St. Lawrence River. In 2020, EPA modified its original cleanup plan to include removal of an additional 90,000 cubic yards of sediment, instead of capping, from an area of the river near Snug Harbor. This additional removal was needed to accommodate a new, larger tugboat purchased by the St. Lawrence Seaway Development Corporation, which operates its tugboat out of Snug Harbor. Dredging was substantially completed at Snug Harbor in 2020. Approximately 110,000 cubic yards of sediment was removed from 20 acres of the river. Clean backfill material will be placed in this area in 2021.

 

Two shoreline support areas will be used in 2021 to store and manage capping material; one is the staging area located near the intersection of County Route 42 and Route 131 in Massena and the other is a newly constructed staging area on Haverstock Road. Clean capping material will be brought to these areas by truck and transported by barge or pipeline to the cap placement equipment on the river. As with previous phases of work, a traffic management plan will be in place to address the increased truck traffic at and near the staging areas. The Alcoa East Plant dock will also be used to support the project. While efforts will continue to be made to minimize traffic impacts, residents should exercise caution when driving in these areas.

Health and safety plans have also been developed to protect workers and area communities while work is underway. The air and river water will be monitored during the work, and the results will be available on Arconic’s project website: www.thegrasseriver.com. Noise and lighting in the work zones will also be monitored. Efforts will be made to mitigate noise generated from the construction activities. The submerged pipeline is expected to help reduce noise levels associated with capping operations during nighttime hours. Mechanical capping will be limited to daytime hours.

Howmet Aerospace Inc. (formerly Arconic Inc.) is responsible for performing the work at the site on behalf of the parties responsible for the Superfund cleanup.