THE OPPORTUNITY
PS&S was retained by National Grid US to permit, design, and provide oversight of the remediation and restoration of an 8-acre section of Coney Island Creek that had been impacted by the operations of the adjacent former Brooklyn Borough Gas Works site (FBBGW).
THE CHALLENGE
Coney Island Creek adjacent to the FBBGW was contaminated by coal tar and DNAPL from the past operations, which had severely damaged the Creekâs ecosystem. There were additional challenges of unstable side slopes, extensive debris, and very large combined sewer outfalls.
THE PS&S SOLUTION
PS&S received approval of an application for a U.S. Army Corps of Engineers (USACE) Nationwide Permit 38 to support the remediation and restoration of Coney Island Creek. PS&S implemented the permit under the inspection of the USACE.
The remedial design included excavation and removal of approximately 58,000 cubic yards of sediment and removal of all NAPL and visible source material from the creek and along the banks. PS&S observed and documented the cleaning of existing rip-rap, retaining walls, and bulkheads which remained in place throughout the remediation.
The creek restoration design included installation of a geotextile separation fabric at the bottom of the creek following excavation and backfilling with a minimum of 3 feet of sediment-quality backfill. PS&S designed an ecological buffer area to restore the habitat damaged by former operations.
PS&S also prepared a second application to the USACE for the permitting and dredging of 58,000 cubic yards of MGP-impacted sediments from the creek. PS&S provided construction oversight and noise and vibration monitoring, as well as groundwater sampling to support a planned groundwater treatment plant.
RELATED PROJECTS
DISCIPLINES INVOLVED
GEOTECHNICAL