USEPA Superfund Mega-Site
Engineered Cap Design Support

Under Sole Source Contract W912WJ-18-C-0003 Lally Consulting LLC (Lally LLC) provided project-defining sediment remediation technical advisory services at the New Bedford Harbor Superfund Site.

At the request of the USACE – New England District, Lally LLC authored the project design guidance for the NBHSS caps to be installed at subtidal locations with contamination that could not effectively be addressed through removal. Based on site physical and chemical conditions, Lally LLC introduced to the project multi-layer engineered caps as the recommended approach for the contamination levels and locations requiring confinement. The cap guidance document provided functional descriptions of physical isolation, chemical isolation, and erosion control layers, cap materials including active components, design and construction considerations, contaminant flux models, and quality control guidance.

Lally LLC was thereafter requested by USACE / USEPA to develop Krig-derived cap designs to ensure a consistent methodology for the site’s seven (7) permanent subaqueous caps. The cap designs accounted for steep slopes, hydrodynamic conditions, integration with intertidal remediation in some cases, and introduced Nature-based engineering techniques to improve habitat conditions and wave attenuation functionality.

Specific Cap Design Services performed by Lally LLC at the request of USACE and USEPA included;

Services Provided

Author Project Cap Design Guidance

Hydrodynamic Modeling for Cap Stability

Educate on SWATH Cap Placement Method

Cap Volume and Production Estimates

Ongoing Cap Quality Control and Production

Production and Quality Control Monitoring Tools

Contaminant Flux (CapSim) Modeling

Propwash and Armor Sizing Calculations

Design Krig‐derived Permanent Caps

Alternative Capping Methods

Slope Stability Analyses

Location

Massachusetts, USA

Period

2017 – 2020

For our work under this contract, Lally Consulting LLC received the highest overall Contractor Performance Assessment Reporting Systems (CPARS) rating of Exceptional from 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.

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