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Syracuse, New York

Onondaga Lake Cleanup

Sustainable Restoration

Onondaga Lake is located northwest of Syracuse, NY, extending 4.6 mi long and 1 mi across. Nearly 100 years of population growth and municipal and industrial activity significantly impacted Onondaga Lake’s water quality and sediments. Manufacturing operations, as well as municipal discharges, resulted in the release of multiple contaminants, including metals, volatile and semi-volatile compounds, and PCBs in addition to inorganic waste material from soda ash production.

Honeywell first conducted a comprehensive environmental study of the area to evaluate the feasibility of various remedial alternatives. Parsons has been involved in the cleanup since the development of the feasibility study (FS) in 2004 and has served as project manager throughout the cleanup and restoration. The multiyear cleanup is one of the largest, most complex U.S. sediment remediation projects—as well as among the largest environmental remediation projects—in New York State.

Remedial Alternatives

For the FS, Parsons assembled a team of 100+ technical experts representing more than 25 consulting firms and dozens of technical disciplines, including biology, lake ecology, hydrogeology, chemistry, toxicology, sediment dredging, sediment capping, civil/environmental engineering, habitat restoration, ecological risk assessment, geology, and groundwater fate. This study assessed practicable options to reduce risks to human health and the environment posed by mercury and chlorinated organics in sediments, wetlands, and surface waters under a consent order with the New York State Department of Environmental Conservation (NYSDEC). The goal was to evaluate a full range of potential remedial technologies and alternatives for the lake and to develop a remediation plan. The remedy outlined in the Record of Decision, issued by the U. S. Environmental Protection Agency and the NYSDEC in 2005, called for:

  • Dredging and disposal of up to an estimated 2.65 million yd³ of contaminated sediments
  • Construction of an isolation cap over an estimated 425 ac in the shallower areas of the lake
  • Construction of a thin-layer cap over an estimated 154 ac in the lake’s deeper areas
  • Construction and operation of a hydraulic control system along part of the shoreline
  • Completion of a pilot study to evaluate methods to prevent formation of methylmercury
  • Wetland and habitat restoration
  • Monitoring natural recovery
  • Long-term maintenance and monitoring
  • Protection of human health and the environment
  • Diversification of the habitat for wildlife
  • Implementation in a timely manner
  • Remediation of this valuable recreational and ecological resource for the community

Parsons employees monitoring water quality

Job Creation

In July 2010, Parsons negotiated a labor harmony agreement with 15 construction unions—represented by the Building Trades Department, the Central and Northern New York Building and Construction Trades Council, and Parsons—to provide remediation construction services for the Onondaga Lake cleanup. Remediation construction services began in 2005 and consisted of constructing an underground barrier wall and adjacent groundwater collection system to intercept contaminated groundwater from reaching the lake. At peak, 500 personnel were working on the Onondaga Lake cleanup, promoting economic growth and bringing technical jobs to the Syracuse area. Many of those involved are local to the Central New York area, with a vested interest and commitment to reviving the lake.

The Cleanup

The cleanup process officially began in 2006 and consisted of four key areas:

  • Prevent the migration of contaminants into the lake from old industrial sites
  • Remove material from the bottom of the lake, permanently containing it at an approved site, and capping designated portions of the lake bottom
  • Create sustainable habitat along the lake’s shoreline and tributaries to encourage wildlife growth and expanding opportunities for local recreation
  • Implement a long-term operation, maintenance, and monitoring program to ensure the effectiveness of the remedy

Parsons was a key member of the cleanup process, with project management duties ranging from strategy to management of construction and labor to dredge materials management. An estimated 2.2 million yd³ of contaminated sediments were dredged from the lake and replaced with clean material in a process called capping. Parsons concluded sediments should be hydraulically dredged and transported as slurry from the lake to the dewatering area, known as the sediment consolidation area (SCA). Advantages of hydraulic dredging include greatly reduced truck traffic and associated engine emissions and noise. More than 500 team members worked in shifts around the clock 6 days a week to complete this project during the seasonal months.

Onondaga Lake

The Lake Makes a Comeback

Parsons has been a part of the Syracuse community for more than 30 years. We have provided engineering, construction, technical, and safety management services for projects throughout Central New York and around the world in a safe and responsible manner since our founding in 1944. For the past 13 years, we have been a part of the team of local and national experts working on the Onondaga Lake cleanup. As a result of our work, and the work of countless others, members of the community surrounding Onondaga Lake are once again able to enjoy the water. Through the cleanup and habitat restoration, wildlife has also returned to the lake in both the shoreline and surrounding wetlands. These efforts have contributed to 184 species returning to the lake and nearby areas and are continued by local groups and volunteers. Parsons sponsored and participated in the Onondaga Cup and LakeFest, an annual rowing competition. In addition to watching the competition, attendees were also entertained by live music, water entertainers, and shore-side activities. Swimming, fishing, and kayaking are also now common occurrences seen on the lake and will be available for generations to come.