A Combined Solution for Sediment Remediation and Waterfront ...
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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 • Capping of Remaining Sediments • On-site Solidification of Dredged Sediments • Preparation for Waterfront Redevelopment Dredging 2012
Location: A Slip in New Bedford Harbor
Manufactured Gas and Tar Plant 1880 - 1960
OUTER SLIP
Dredging 2012
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
Remediation – Plan View
Sheet Pile Walls
Cell 2
Inner Slip ISS & Fill Area
Water Treatment Facility
Cell 1
Dredged Areas for Tar Removal
ISS Mixing Plant
Capping Area Fixed Turbidity Curtain
Dredged Area for Cap Installation
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
Dredging Behind Dual Curtains & Booms
Dredging 2012
Dredging of Outer Slip
Vapor & Odor Suppression Foam
Dredging 2012
GPS Positioning of Dredge Bites
Capping of Remaining Sediments
Benthic Sand – 12 inches
Stone Armor – 3 inches Gravel – 3 inches AquaBlok – 6 inches
Sand Fill – thickness varies
AquaBlok
Dredging 2012
Cap Placement
Dredging 2012
Solidification: Inner Slip – Section View New Sheet Pile Closure Walls Existing Bulkhead Cell 2
Cell 1
Mean High Water Mean Low Water
Top of Dredge Spoils Top of Sediments
Top of Bedrock (El. -24.2)
Top of Bedrock (El. -39.0)
Top of Dredge Spoils
Soil Mixing to Solidify Sediments
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
Site Ready for Waterfront Development
Dredging 2012
Thank You
Questions?
Dredging 2012
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
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
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
Dredge Cut Lines Tolerance Near Bulkheads
Min. Max.
Tolerance In All Other Areas
El -14.
Min.
El -14.5
Max.
Dredging 2012
El -14.
El -15.
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 • Capping of Remaining Sediments • On-site Solidification of Dredged Sediments • Preparation for Waterfront Redevelopment Dredging 2012
Location: A Slip in New Bedford Harbor
Manufactured Gas and Tar Plant 1880 - 1960
OUTER SLIP
Dredging 2012
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
Remediation – Plan View
Sheet Pile Walls
Cell 2
Inner Slip ISS & Fill Area
Water Treatment Facility
Cell 1
Dredged Areas for Tar Removal
ISS Mixing Plant
Capping Area Fixed Turbidity Curtain
Dredged Area for Cap Installation
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
Dredging Behind Dual Curtains & Booms
Dredging 2012
Dredging of Outer Slip
Vapor & Odor Suppression Foam
Dredging 2012
GPS Positioning of Dredge Bites
Capping of Remaining Sediments
Benthic Sand – 12 inches
Stone Armor – 3 inches Gravel – 3 inches AquaBlok – 6 inches
Sand Fill – thickness varies
AquaBlok
Dredging 2012
Cap Placement
Dredging 2012
Solidification: Inner Slip – Section View New Sheet Pile Closure Walls Existing Bulkhead Cell 2
Cell 1
Mean High Water Mean Low Water
Top of Dredge Spoils Top of Sediments
Top of Bedrock (El. -24.2)
Top of Bedrock (El. -39.0)
Top of Dredge Spoils
Soil Mixing to Solidify Sediments
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
Site Ready for Waterfront Development
Dredging 2012
Thank You
Questions?
Dredging 2012
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
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
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
Dredge Cut Lines Tolerance Near Bulkheads
Min. Max.
Tolerance In All Other Areas
El -14.
Min.
El -14.5
Max.
Dredging 2012
El -14.
El -15.
