Onondaga Lake

The Onondaga Lake cleanup, one of the largest remediation projects in the country, has been completed under the supervision of the New York State Department of Environmental Conservation (DEC), the New York State Department of Health (DOH), and the U.S. Environmental Protection Agency (EPA).

The cleanup plan called for removing material from the lake bottom, installing a new bottom cap in some areas, improving habitat, and transporting and containing dredged materials. Hydraulic dredges were used to remove the lake material. It was then transported via a double-walled pipe through non-residential areas to the consolidation area, where it was processed and pumped into geotextile tubes for drying and safe isolation long-term. Water is collected and treated to meet DEC standards before being returned to the lake. Extensive efforts were incorporated into the design and operation to protect worker and public health.

Dredging was completed in 2014, a year ahead of schedule. Capping was completed in 2016. Habitat restoration, a major focus of Onondaga Lake’s remediation and restoration, was completed in 2017.

The cap, which creates a new, clean lake bottom, consists of more than 3 million cubic yards of natural materials placed over 475 acres of the lake bottom. In locations where dredging occurred and adjacent areas, the new lake bottom cap was added to permanently isolate any remaining contaminants. Extensive modeling and testing by national experts were part of the design process. The top portion of the cap will function as a habitat layer where fish and other organisms interact with the new, clean lake bottom. The habitat layer will improve lake bottom conditions and fish spawning.

Natural recovery addresses deep water portions of the lake. During the summer months, the deep water is treated to reduce levels of mercury that would accumulate in fish. In its First Five-Year Review Report of the Onondaga Lake Bottom Subsite in 2015, EPA stated, “natural recovery in the Lake is progressing faster than predicted.”

Honeywell is implementing a comprehensive Onondaga Lake Monitoring and Maintenance Plan under the oversight of DEC and EPA to ensure the remedy meets the long-term objectives outlined in the cleanup plan.

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