USEPA New Bedford Harbor Superfund Site
Environmental Consulting Professional Services Subcontract
One of the United States Environmental Protection Agency’s (USEPA’s) largest cleanup sites, the 18,000-acre New Bedford Harbor Superfund Site (NBHSS) is an urban tidal estuary with sediments (formerly) contaminated with high levels of polychlorinated biphenyls (PCBs) and heavy metals.
The United States Army Corps of Engineers – New England District (USACE) has been supporting USEPA on this project since the mid‐1980s with initial efforts focused on site investigations and feasibility studies, followed by on‐site pilot studies of dredges and dredged material disposal techniques. From 2004 to 2015, dredging, sediment dewatering and wastewater treatment activities for the mass removal of sediments, transport and disposal and related activities at the site were completed by a Remedial Action Contract (RAC) Contractor team.
Based on work on the New Bedford Pre-Design Field Test in 2000 and other EPA sediment remediation mega-sites, Lally Consulting LLC (Lally LLC) was requested by the USACE in 2015 to provide dredging and sediment remediation expertise to USACE, USEPA and their multidisciplinary RAC Contractor team for the cleanup of over 200 subtidal acres of PCB-contaminated sediment within the Upper and Lower Harbors of the NBHSS.
Under Environmental Consulting Services Contract W912WJ-12-D-0004, Lally LLC was subcontracted as Sediment Remediation Expert to contribute to the development of several planning, engineering and implementation efforts to move the site towards cleanup. Initially providing technical support on the project’s confirmatory sampling approach and cleanup strategy development, the scope of Lally LLC’s work was requested to expand to provide engineering design and operations technical expertise to the project team.
The scope expansion included design of precision mechanical dredging and capping technologies, components, and methods; remedial design guidance for dredging and capping; plans & specifications development; hydraulic and mechanical dredging performance reviews, optimizations, and best practices implementation; management unit development, sediment sampling and dredge prism design improvements; residuals management, construction oversight and quality control guidance; and other remedial design and operations technical support.
The work involved numerous meetings on site, at USACE-NAE headquarters and remotely, and work products submitted on an expedited basis. Lally LLC’s sediment remediation technical support services were requested on multiple remedial action contracts across the Lower and Upper Harbors, including foremost the Interim Remedial Action Contract (IRAC) for the removal and processing of the sediments from the Upper Harbor with the highest contamination levels, and the Best Value (BV) contract with disposal of less contaminated dredged material into the Lower Harbor Confined Aquatic Disposal CAD Cell (LHCC).
How we Helped
Specific work completed by Lally LLC for USACE and USEPA under this subcontract included;
- Led the changes to Hybrid Precision Mechnical / Hydraulic Transport and Precision Mechanical Excavator Dredging Approaches for remaining Upper and Lower Harbor Remediation Contracts.
- Led change from existing (2004-2015) ‘Z-Block’ dredging design approach to Precision Contour methodology.
- Educate RAC A/E Contractor on how to design precision dredge prisms.
- Introduce the concepts of Core Confidence and Geostatistical Interpolation (Kriging and Thiessen polygons) to the project for more accurate Dredge Prism Design.
- Develop Contour Dredging Plans, cross section drawings, and electronic dredge prism files for numerous Dredge Management Units.
- Contribute to project Confirmatory Sampling and Analysis Plan, including determining optimal sampling frequency for project design, pre-dredge and post-dredge confirmatory sample locations.
- Improve NBHSS project Core Sampling Program through education and implementation of Data Quality Objectives (DQOs).
- Introduce new project Hydrographic Survey methods and applications.
- Identify and quantify specific uncertainties for bathymetric survey and core sampling. Proposed side-by-side vibracore and piston core field study and provided guidance on equipment, procedures and best practices.
- Guide modifications to the Lower Harbor Best Value Remedial Dredging contract design, performance requirements, production rates, and contract documents at all phases (30%, 70%, 100% Design).
- Develop Comprehensive Plan outline for Upper Harbor Subtidal and Intertidal projects.
- Develop Project Data Needs document.
- Perform in-depth evaluation of the incumbent (2004-2015) Hydraulic Dredging process for the Cleanup Phase of Upper Harbor project.
- Author the NBHSS Cleanup Phase Dredging Program, including evaluation and recommendations on dredge types, sizes, numbers, processing and support equipment details, production and cost models, and other management and quality control measures to optimally bring the NBHSS Upper Harbor to a successful cleanup.
- Oversee implementation of recommendations through ongoing NBHSS technical support per USACE and USEPA.
- Develop a Daily Inspection Checklist for Project Quality Control and Quality Assurance.
- Review daily progress reports, surveys, and other data, make ongoing recommendations on dredge performance and methods.
- Make recommendations focused on Minimizing Generated Residuals and getting to clean more efficiently i.e. dredging practices, sequencing, lane management.
- Educate RAC Contractor on Environmental Bucket Design. Develop bucket overlap and fill diagrams and tables for project-specific equipment.
- Oversee Startup and Implementation of Precision Dredges and Dredge Prisms.
- Develop Design Improvements for Lower Harbor CAD Cell Turbidity Curtain. Provide new curtain design concept.
- Author NBHSS Project Engineered Cap Design Guidance at the request of USACE.
- Identify Need and Prepare Scope of Work for Project Ice Engineer to conduct scour mechanism analyses as part of remedial design.
- Review multiple Contractor Work Plans, Quality Control Plans and Long-Term Monitoring Plans. Provide recommendations and guidance as requested by USACE and USEPA.
- Monitor progress of Remedial Action Contractors dredging for Upper Harbor. Conduct Performance Evaluations on site and remotely per USACE and USEPA.
- Perform analyses of progress surveys and Electronic Dredge Data to assess and improve performance across several areas i.e. Accuracy, Residuals and Production.
- Initiate Dual-frequency Bathymetric Survey Accuracy analysis.
- Develop Pre- and Post-dredge Sample Location Map, provide inputs on resampling locations.
- Participate in conference calls with RAC Contractor to review guidance and expectations.
- Prepare Presentations on Dredge Performance, Residuals, Accuracy for review with Project team.
- Developed a DELFT3D Hydrodynamic Model for the New Bedford Harbor Superfund Site.
Related Projects
Services Provided
Precision Contour Dredge Plan Design
Contract Plans and Specifications Development
Sediment Remediation Education and Guidance
Site Investigations
Sediment Sampling Program
Establish Dredging Performance Metrics
Dredge Equipment and Operations Improvements for Production, Accuracy and Cleanup Efficiency
Water Management
Contractor Negotiations
Capping Design Guidance
CAD Cell Management
Hydrodynamic Modeling
Location
Massachusetts, USA
Period
2015 – 2017
Lally Consulting LLC received an overall Exceptional rating for its work completed under this subcontract.