It is not news that the , for it’s been filled with coal tar, raw sewage and heavy metals for a century, but it is news that there is a tangible plan on how to actually clean it up.
On Monday, the Environmental Protection Agency, which added the polluted canal to its Superfund National Priorities List in March 2010, revealed their remedy plan, but stressed that it’s still in the draft phase.
During the Gowanus Canal Community Advisory Group meeting, Christos Tsiamis, the EPA's Gowanus Canal Project Manager, gave a three-hour explanation of how his agency plans remove the toxins from one of the most polluted waterways in the nation.
“There is a massive source of migrating liquid tar and we need to take care of it,” Tsiamis said. “We are insisting on controlling the source, because once that’s removed the leftover material will be less concentrated and less dangerous.”
Tsiamis explained that there are three major sources of coal tar: Fulton, Public Place and Metropolitan, all of which were formerly Manufactured Gas Plants, or MGP sites. The coal tar in the soil of these sites continues to leak into the canal through the bulkheads.
Public Place, which is located between along the canal between Fifth and Huntington streets, is the biggest source of the sludge. National Grid, which is responsible for cleaning up the site, has so far.
Tsiamis also said that other toxins add to the pollution, especially Combined Sewer Overflows (CSOs), which contains storm runoff and raw sewage.
The EPA’s feasibility plan has two concerns, source control and fixing the bulkheads. The project will begin at the top of the canal, near Douglass Street and work its way down to the mouth, cutting the canal into three areas. Area 1, from Douglass Street to First Street; Area 2, from First Street to Hamilton Avenue; and Area 3, from Hamilton Avenue to the mouth of the canal.
Tsiamis did not want to give many hard numbers, but did estimate that the EPA will have to dredge around 500,000 cubic yards of sediment from the bottom of the canal in order to excavate the contaminated soil.
The dredging will occur in three phases in the three areas. It is not certain yet, but one plan would be to partially dredge Areas 1 and 3 and full dredge Area 2, since Public Place is the main source of pollution.
But the contamination is so deep that no matter what there will be leftover tar: “We found that there was no clean and reliable surface, so some will be left behind,” Tsiamis said.
When asked how deep they will dredge, Tsiamis stated: “I cannot give you an answer right now, but my goal is to leave a sustainable clean bottom.”
After the removal of the bottom of the canal, the new surface will be capped in order to prevent leftover liquid tar from seeping up from the bed and migrating to the surface and throughout the water.
Tsiamis explained that the capping will have a combination of layers in order to “sustain life.” The first layer would try to solidify the liquid tar with an oilophilic mat, which attracts and absorbs oil, and then there will be a couple feet of sand and then another level of gravel.
The 500,000 cubic yards of dredged sediment, which will be toxic sludge, or “black mayonnaise,” will have to go somewhere. Tsiamis said the last resort is to pick up the sediment and drive it to a landfill, so the EPA is hoping to rely on onsite treatment. They will solidify the sediment and then put it in containment units, or use it to make concrete for the bulkheads.
If the sediment needs to be treated offsite, then they will try to rely on barges to bring it to New Jersey or upstate New York. They are also going to see if the sediment can be turned into coal through cogeneration.
The EPA hopes to finish the project by 2020.
“This will not be a situation where we go, we clean and you have your shorelines done, this is going to take a long time,” Tsiamis said.
After it is all said and done there will be a five-year period when the EPA observes, maintains and issues a final report to the public.
But, that said, it does give the public a lot of time to voice their concerns and try to get as much done for the canal and community as possible.
“This is an ideal time to address every concern we have with the canal,” Tsiamis said. “If most of the concerns are not corrected now, then it’s never going to happen. This is the biggest concentrated effort with the best expertise, this will not happen again.”
The Feasibility Plan will be ready for the public eye, and public suggestions, before Christmas.
After Tsiamis’s near three-hour presentation, which was mixed with questions from the CAG members, a member brought up the canal’s water quality, since it was in fact a Water Quality meeting. He asked how the EPA will address that issue in the proposed remedy.
“We are a construction project. I am aware of the history and of the community’s demands, but this is a conversation for the Clean Water Act,” Tsiamis said. “But our project will greatly reduce the toxins in the canal. We are addressing the human health risk of exposure and it will address your concerns more quickly than the Clean Water Act will.”