Gowanus Canal, Brooklyn, NY

Gowanus

superfund

The public
Site Description[1] 
The Gowanus Canal is a man-made navigational waterway in southeastern Brooklyn, Kings County NY. Nearly the entire canal is bounded by “hard” urban shorelines in the form of bulkheads, moorings, and retaining walls. The site definition includes only the canal and its attached barge slips, totaling slightly over 1.5 linear miles of waterway. Averaging 100 feet in width, the open water area defined as the site totals approximately 1,000,000 square feet or 29 acres. The canal also serves as a storm water drain for the surrounding area. Currently, approximately six square miles of highly urbanized land drains into the canal. Sanitary sewers no longer discharge directly; however, numerous combined sewer overflows (CSO) continue to discharge to the canal during storm events. Industrial discharges from a wide variety of industrial processes were also historically routed to the canal, via private discharge pipes or the municipal sewers. Stagnant water conditions have plagued the canal since its initial construction. To combat this, a “flushing tunnel” at the north end of the canal was constructed in 1911 to divert water from the Buttermilk Channel to maintain flow through the canal to Gowanus Bay. Operation of the flushing system has had numerous problems resulting in lengthy periods during which it was inoperable. Significant upgrades to this system are scheduled over the next few years to increase the volume of water flushing the canal.

Site History: Prior to European settlement, this area formed a large tidal marsh, drained by Gowanus Creek and surrounded by higher ground to the west (present-day Carroll Gardens) and east (present-day Park Slope). In the mid 1800s, the Canal was constructed, more or less along the alignment of Gowanus Creek, by straightening and deepening the stream channel and dumping the excavated materials behind rows of timber piles along the shoreline. Combined with other urban filling activities in the surrounding area, the result was a large area of reclaimed land with a dendritic, dead-end canal providing barge access through the middle. The canal offered barge access far inland into Brooklyn, effectively increasing BrooklynÂ’s available tidewater frontage for water-borne commerce. Development of the area was rapid, and by 1869, the layout of the canal and the local street network were essentially complete. Long term decline of the local manufacturing economy has led to a marked decrease in commercial use of the Canal, with only a handful of petroleum distributors and concrete batch plants as regular users. Roughly the northern half no longer hosts barge movements as a result of siltation due to the significant CSOs which discharge street waste and sewage solids. The canal has not been dredged in several decades, consequently, substantial amounts of sediment have been deposited in upstream areas, and water depths approach zero at low tide. The sediment consists largely of solids settled from stormwater and CSO discharges. Presumably, industrial discharges to the canal have diminished in line with the de-industrialization of the surrounding neighborhood, although this is difficult to verify directly due to a lack of historical records for comparison. The site was listed on the NPL on March 2, 2010. The listing applies only to the canal itself. Upland sites remain under DEC management.

Summary of Project Completion Dates
Projects associated with this site are listed in the Project Completion Dates table and are grouped by Operable Unit (OU). A site can be divided into a number of operable units depending on the complexity of the site and the number of issues associated with a site. Sites are often divided into operable units based on the media to be addressed (such as groundwater or contaminated soil), geographic area, or other factors.

Site Environmental Assessment
Water quality issues have plagued the Gowanus Canal almost since its construction. Tidal flushing is largely ineffective due to the length, narrowness, and circuitous layout of the canal channel. Operation of the flushing tunnel has improved the situation during the years when flushing was being conducted; however, the current tunnel requires significant upgrades and is likely to be off-line for a year or more as the upgrades are performed. The canal is currently classified by NYSDEC as Class SD water body, acknowledging that natural or man-made conditions limit attainment of higher standards. Even the SD standards are not currently met. Oily sheens are common on the water surface during low tides, dissolved oxygen levels are low and surface contamination has been identified. Sediment quality is also low. Ongoing CSO discharges have resulted in extensive deposits of settled solids, particularly in the more sheltered areas near the upper end. Some parts of the canal bottom are exposed at low tide. Another particularly important contributor to sediment quality problems is the presence of three former manufactured gas plant (MGP sites) along the length of the canal. Although all three MGPs have been closed for decades, coal tar-impacted sediments have been identified at numerous locations along the length of the canal. The three MGPs are all covered by cleanup agreements with NYSDEC, and are at various stages of investigation,remedy selection and implementation. The Fulton Works, immediately east of the canal at its northern extremity, is in the Remedial Investigation process. The Carroll Gardens site (also widely known as Public Place) is in the Brownfield Cleanup Program, and is slated for remediation and redevelopment as a mixed commercial/residential project. The former Metropolitan works, immediately south of the 9th Street bridge, was partially redeveloped under a Voluntary Cleanup Agreement in 2002-2003. However, more work remains to be done–part of the MGP facility lies beneath an active retail building. A Remedial Investigation began in March 2010. Numerous oil storage and handling facilities, asphalt plants,manufacturing facilities and chemical, paint, fertilizer and plastic manufacturers have, or continue to, operate along the canal.

Site Health Assessment

People using the canal for recreational purposes such as swimming and boating may come into direct contact with chemical contaminants and harmful biological organisms. People should avoid any activity that would result in swallowing or accidentally ingesting Canal water. Additionally, people using the canal for any purposes should wash their hands or shower after contacting the water, especially before eating and at the end of the day. Those people who are considering eating fish and shellfish caught in the Canal should follow the NYSDOH consumption advisory for fish and shellfish taken from the Upper Bay of New York Harbor. This advisory specifically includes: • The NYSDOH recommends that women of childbearing age and children under the age of 15 not eat any fish from the Canal. • Other people should eat no gizzard shad, white perch and crab hepatopancreas and crab cooking liquid. Also, other people should eat no more than one meal per month of American eel, Atlantic needlefish, bluefish, rainbow smelt and striped bass. • People should eat no more than one (1/2 pound) meal per week of all other fish species except blue crab meat (six crabs per week).

Contaminants of Concern
Type of Waste Quantity of Waste
COAL TAR PITCH VOLATILES UNKNOWN
COPPER UNKNOWN
DDE UNKNOWN
LEAD UNKNOWN
MERCURY UNKNOWN
PCB-AROCLOR 1242 UNKNOWN

  1. DEC Environmental Site Remediation Database.  Site Name: "Gowanus Canal Site".

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