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A Combined Solution for Sediment Remediation and Waterfront Development John T. Finn, P.E.

. A Combined Solution for Sediment Remediation and Waterfront Development John T. Finn, P.E. GEI Consultants, Inc. Dredging 2012. The Problem. Dredging 2012. A Complex Problem: A Combined Solution : John Finn, GEI. Removal of Sheen-Producing Sediments Protection of Existing Bulkheads

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A Combined Solution for Sediment Remediation and Waterfront Development John T. Finn, P.E.

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  1. . A Combined Solution for Sediment Remediation and Waterfront Development John T. Finn, P.E. GEI Consultants, Inc. Dredging 2012

  2. The Problem Dredging 2012

  3. A Complex Problem: A Combined Solution :John Finn, GEI • Removal of Sheen-Producing Sediments • Protection of Existing Bulkheads • Capping of Remaining Sediments • On-site Solidification of Dredged Sediments • Preparation for Waterfront Redevelopment Dredging 2012

  4. Location: A Slip in New Bedford Harbor

  5. Manufactured Gas and Tar Plant 1880 - 1960 INNER SLIP OUTER SLIP Dredging 2012

  6. Minimum Remedy Requirements Outer Slip: - Remove all sheen-producing sediment in top foot - No off-site disposal: Place all dredged sediment in Inner Slip - 2-foot Composite Cap Inner Slip - Solidify dredged sediment and existing sediment/soil to bedrock - Prepare the site for waterfront redevelopment Dredging 2012

  7. Remediation – Plan View Water Treatment Facility Sheet Pile Walls Cell 2 Cell 1 Dredged Areas for Tar Removal ISS Mixing Plant Inner Slip ISS & Fill Area Dredged Area for Cap Installation Capping Area Fixed Turbidity Curtain

  8. Dredging Requirements and Constraints • Protection of bulkhead stability • Final elevation allows sufficient draft for boat traffic • Limited capacity of Inner Slip: - Account for expansion upon solidification - Account for expansion/settling upon dredging/placement Dredging 2012

  9. Dredging Behind Dual Curtains & Booms Dredging 2012

  10. Dredging of Outer Slip

  11. Vapor & Odor Suppression Foam Dredging 2012

  12. GPS Positioning of Dredge Bites

  13. Capping of Remaining Sediments Benthic Sand – 12 inches Stone Armor – 3 inches Gravel – 3 inches AquaBlok – 6 inches Sand Fill – thickness varies

  14. AquaBlok Dredging 2012

  15. Cap Placement Dredging 2012

  16. Solidification: Inner Slip – Section View New Sheet Pile Closure Walls Existing Bulkhead Cell 2 Cell 1 Water Treatment Facility Mean High Water Mean Low Water Top of Dredge Spoils Top of Dredge Spoils Top of Sediments Top of Bedrock (El. -24.2) Top of Bedrock (El. -39.0)

  17. Soil Mixing to Solidify Sediments

  18. Dredging, Capping, and ISS Statistics • 1,350 cubic yards dredged • 18,000 ft2 dredge area • 190 - eight foot diameter ISS columns • 37 - three foot diameter ISS columns • 7,000 - cubic yards of sediment and soil mixed • 427 ton of AquaBlok

  19. Site Ready for Waterfront Development Dredging 2012

  20. Thank You Questions? Dredging 2012

  21. Post-Scripts • Environmental Business Council’s 2012 Award for Collaboration • Study of In-Situ Solidification of Contaminated Sediments, Sponsored by the Electric Power Research Institute (EPRI) Dredging 2012

  22. Coordinating Multiple Agencies • MassDEP leadership streamlined complex permitting • Reached out to federal, state & local regulators • Coordinated multi-agency team approach • Hosted & facilitated 2 critical multi-agency meetings  • Public engagement • Public notice soliciting public comments on 10/23/2010 • Public meeting on 12/8/2010 with USEPA and MassDEP • Innovative MCP site closure strategy

  23. Permitting and Legal Framework • MassDEP • Release Abatement Measure Plan • 401 Water Quality Certification • Chapter 91 License • EPA – TSCA 61C • Risk-Based Cleanup Plan • U.S. Army Corps of Engineers, New England District • Category 2 General Permit • New Bedford Conservation Commission - Wetland Order Of Conditions • Property Owner Agreement: Fueling Terminal Ops Dredging 2012

  24. Dredge Cut Lines Tolerance Near Bulkheads Tolerance In All Other Areas Min. Min. El -14. El -14. El -14.5 Max. Max. El -15. Dredging 2012

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