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Full-scale dredging this summer at Onondaga Lake

June 5th, 2012 / By: / Geotextiles

Geotextile tubes are instrumental in the $451 million Superfund remediation project in upstate New York

Dredging and capping of contaminated sediments in Onondaga Lake is set to begin this summer, according to a press release from the New York State Department of Environmental Conservation (DEC).

The $451 million Superfund remediation project in Syracuse, N.Y., has undergone five years of design and engineering, with preparation for full-scale dredging and capping operations now under way. Honeywell International is conducting the project with oversight by the DEC, the U.S. Environmental Protection Agency (EPA), and the New York State Department of Health (DOH).

“The cleanup of Onondaga Lake has made tremendous progress over the past several years through cleaning up industrial pollution sites and Onondaga County’s state-of-the-art wastewater treatment projects,” said DEC commissioner, Joe Martens.

“Onondaga Lake will now undergo perhaps one of the largest, most complex, and advanced dredging projects in the nation that will benefit the environment and public health while helping the community through increased economic activity, said Martens. [This] has been a long time in the making and was made possible through the cooperative efforts of DEC, EPA, DOH, Honeywell, SUNY College of Environmental Science and Forestry, and the local communities surrounding the lake.”

The release said that the dredging project is scheduled to be fully operational later this summer. Activities such as debris removal and equipment testing will be taking place during the next several weeks. Honeywell said it estimates that more than 500 central New York scientists, engineers, and laborers are working on the project, and Honeywell plans to hire more local workers as the project continues.

Industrial activities located on or near Onondaga Lake contributed to a variety of industrial contaminants affecting the lake, including mercury and other metals.

Dredging will be performed in 185 acres of the lake, which represents approximately 6% of the 3,000-acre lake bottom. In addition, dredging will be performed in 21 acres in three areas adjacent to the lake. The estimated volume of materials to be removed is approximately two million cubic yards.

Sediment will be hydraulically dredged and transported by a double-walled pipe to the lined consolidation area where it will be pumped into geotextile tubes for drying. Once the dredging has been completed, the geotextile tubes will be capped, and water removed from the tubes’ sediment will be collected and treated to meet water quality standards before it is returned to the lake.

The release noted that completion of dredging is expected by 2015 and completion of capping operation is scheduled by 2016 in Onondaga Lake. Habitat restoration activities to be performed in all remediated areas are anticipated to be completed in 2016.

The Onondaga Lake Superfund cleanup plan includes the following components with the goal of protecting human health and the environment:

  • removing material from the bottom of the lake by hydraulic dredging.
  • capping 417 acres of the lake bottom, approximately 14%, to isolate the underlying contaminated materials from the environment.
  • restoring habitat in areas where dredging or capping occurs.
  • addressing the deeper portion of the lake by measures such as thin layer capping over 27 acres, nitrate addition, and monitored natural recovery.
  • implementing a long-term operation, maintenance, and monitoring program to ensure the effectiveness of the remedy.

In 1994, Onondaga Lake and upland source areas were added to the EPA’s Superfund National Priorities List. The dredging, capping, and habitat restoration work that is about to begin in Onondaga Lake is a major component of a larger, comprehensive remedial program that encompasses 11 additional sites around the lake. These sites are in various stages of cleanup to eliminate or reduce contaminant sources to the lake.

This includes remedial work in some of the lake’s tributaries (including Geddes Brook, Ninemile Creek, and Harbor Brook), remedial work at former plant sites (including the former LCP/Bridge Street Plant, which was the largest source of mercury to Onondaga Lake), plus remedial work along lakeshore areas where groundwater collection systems have been installed, according to the press release.

The release said that dredging and capping activities are scheduled to take place 24 hours a day, six or seven days a week for five years from early spring to late fall, weather permitting. Lake habitat will be re-established and improved on dredged and capped areas.

More information in a January 2012 GeosyntheticsMagazine.com article.

Source: New York State Department of Environmental Conservation

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