Case Study: Abandoned Cos Cob Power Plant
Site Visit to Cos Cob Park: May 18, 2015
Formerly the Cos Cob Power Plant
Host: Jim Michel, Senior Engineer, Greenwich DPW. Jim has been involved with the Cos Cob Park project for the last four to five years.
MA attendees: Connie Bennett, Phil Crosland, Mardi Dickinson, Townsend Dickinson, Roma Stibravy, Charlie Taney, David Westmoreland
- 1907 plant opens on 9.5 acres on the banks of the Mianus River near where it empties into LIS
- 1907-1986 provided power for railroad line, burns coal, coal ash dumped on the site
- 1986 plant closes
- 1989 Town of Greenwich takes over ownership
- 1997 planning begins
- 1999-2000 plant demolished and plant facilities site remediated
- 2000-2011 remediation planning & research, studies/debate on site use, decision made to create a park, park design completed
- 2011-2015 coal ash remediated from ground surrounding plant site, building of park.
- 2015 Cos Cob Park opens (Site map attached. Land recreation only, no swimming or boating.)
Cost of Plant Demolition and Site Remediation
- Demolition of plant and remediation of plant materials: $4 million, with $2 million of Grant funding
- Remediation of coal ash: $6 million, with $2 million of Grant funding
- Creation of park landscape and facilities: $6.5 million, all Town Capital Funding. Some of the funding was used to improve adjacent roads and streets to provide better access to the park from train station and neighborhood.
- Grant funding was a combination of CT DEEP, EPA and small amount from CL&P.
- Plant facility: Asbestos was present and there was some minor PCB contamination. About half the 9.5 acres was occupied by the physical plant facilities.
- Grounds: About half of the 9.5 acres. Heavy metals are present in the coal ash that was dumped on the grounds. Based on extensive research, the Town of Greenwich is satisfied that the contaminants in the coal ash are not, and will not, leach into the Mianus River and Long Island Sound. This is consistent from what the Manresa Association has been told about the Norwalk site. The bad news about coal ash is that it contains heavy metals. The good news is that these heavy metals tend not to migrate, but stay where they are deposited.
- Comparison of Cos Cob site to Manresa:
- The Cos Cob plant was built in the early 1900’s, a completely different structure than the Manresa plant, built in the late 1950’s.
- Entire 9.5 acre Cos Cob site had coal ash contamination, less intense in area where buildings were, but still present. Manresa has 55 acres of coal ash contamination in Area of Concern #1. Also, Manresa has further coal ash and organic compound contamination in Area of Concern #4, an additional 40 acres.
- There are no wetlands on the Cos Cob site, while there are both freshwater and tidal saltwater wetlands on the Manresa site. There was a requirement in Cos Cob to replant a section of spartina in the low tide exposed area. This was a requirement of ACOE due to disturbance to shoreline.
- Super Storm Sandy had zero encroachment on the Cos Cob site. Sandy put 90% of Manresa underwater.
- Species of Concern. For Cos Cob, Jim Michel is not aware of any specific requirements that had to be addressed. Osprey utilize the cell towers for nesting areas. Manresa has at least six (Diamondback Terrapin, Osprey, Piping Plover, Oystercatcher, Least Tern, American Bittern).
- Plant facility: Asbestos and minor PCB’s were removed.
- Grounds: Open areas were capped with four feet of clean fill (dirt, rocks, clay). Covered areas (parking, playing fields, playground) were capped with two feet of clean fill and a hard cover. A filter fabric covers the clean fill in both cases.
- Metcalf and Eddy, now AECOM: Global firm, Rocky Hill office. Remediation planning, design, coordination. Provided on-site engineer though out the remediation process. (remediation consultant)
- RC&D: Rhode Island based. Handled coal ash remediation and park construction. Contractor
- Milone & MacBroom: Cheshire, designed park (park design consultant)
- Osprey Engineering- Consultant for Asbestos removal from building
- Marin Environmental- Consultant for PCB contamination in building
Other notes of interest
- A 9/11 memorial is about to be built in the park. This is being provided as a gift to the Town from a private group and is fully funded and managed by the private group. The cost of the memorial is approximately $550K.
- An operating transmission station remains directly adjacent to the park and presents minimal issues. It does have a playing field in close proximity, however all facilities are located far enough from the area that they fall well below exposure limits.
- The Manresa Association will seek a meeting for further learning with Peter Berg, head of the Cos Cob Neighborhood Association, and a major advocate for the development of Cos Cob Park.
- The MA may visit the Greenwich DPW’s Engineering Department for some further fact checking.
Note: Jim Michel has reviewed these notes and has encouraged the Manresa Association to interview other sources from Greenwich who have a longer history on the Cos Cob Park project. Jim also encouraged the MA to speak with Gabriella Circosta Cohee of his Division when she returns from maternity leave in early July.