New Bedford Harbor Superfund Site
Final Dredge Plan Designs
After more than 40 years of studies, planning, design and remediation, in 2020, the final subtidal dredging necessary to achieve the New Bedford Harbor Superfund Site ROD action levels was on the horizon.
As requested by USEPA and USACE, Lally LLC had the honor of designing the final subtidal dredge plans for New Bedford Harbor Superfund Site. Identified as South of Wood Street (SWS) and Management Units U, V and W, these areas would also employ precision mechanical dredging approaches. With depths of less than 2 ft. at low tide in the channel thalweg, restrictive widths, and several hard bottom areas, the SWS site, located at the very north end of the Upper Harbor posed significant access challenges, evaluated closely during the design phase. The solution was to perform access dredging in order to create a flotation basin at low tide, and to employ a land-based long-reach excavator to assist in removing the areas not accessible by the floating dredge platform. Once coordinated with the RAC Contractor, the final NBHSS subtidal dredging was undertaken and successfully completed.
How we Helped
Specific work executed by Lally LLC under this final phase of the subtidal NBHSS remediation included;
- Perform Field Reconnaissance of South of Wood Street for dredge planning, design and construction.
- Assess Sediment Data Gaps and develop Sampling Plan for South of Wood Street and final subtidal Upper Harbor dredge areas (MUs U, V, W).
- Normalize and apply Data Quality Objectives (DQOs) to core data.
- Perform Geostatistical Interpolation (Kriging) and analysis to determine PCB distribution employing GIS.
- Incorporate updated Bathymetry, Tides Analysis, Hardpan Delineation, and Sample Data Analysis.
- Identify Need and Design Flotation Basin
- Identify Need and Request Underground Utilities Investigation
- Develop Dredge Plans including PCB distribution (Krig) maps, sample data analysis, removal thickness design, and Dredge Prisms and Electronic Points Files for remaining NBHSS Dredge Areas.
- Coordinate with RAC Contractor for implementation.
- Drive guidance for 100% Production Increase.
- Monitor Dredging Performance in the field
- Monitor Confirmatory Sampling results
- Develop Calculations of Mean Total PCB concentrations in dredge prism designs by interval and area using GIS zonal statistics for LHCC CAD cell management.
- Contribute to final Site Wide SWAC Calculation.
Related Projects
Services Provided
Field Investigations
Sampling and Analysis Plan
Geostatistical Analysis
Dredge Plan Development
Underground Utilities Investigation
Construction Oversight
Quality Assurance and Performance Review
Location
Massachusetts, USA
Period
2019 – 2020
For its work under this contract, Lally Consulting LLC received a Contractor Performance Assessment Reporting Systems (CPARS) rating of Exceptional by the Federal Government.
For its work under USACE Contract W912WJ-18-C-0003, Lally Consulting LLC was nominated by the NBHSS Project Leadership and selected by an awards panel of EPA representatives from across the Agency as the 2020 national recipient of the USEPA Administrator’s Award for Outstanding Accomplishments by a Small Business Contractor.