Confined Aquatic Disposal (CAD) Cells
Planning, Engineering and Management Support
USEPA’s New Bedford Lower Harbor Confined Aquatic Disposal (CAD) Cell (LHCC) was designed to safely contain over 300,000 cy of less contaminated sediment from the New Bedford Harbor Superfund Site. Developed and constructed in several phases, under different contracts, the LHCC has served to greatly increase the extent of remediation possible at NBHSS.
Under Sole Source Contract W912WJ-18-C-0003 Lally Consulting LLC (Lally LLC) was requested by USEPA to assist with several technical evaluations, designs and management of the LHCC with respect to safely optimizing its capacity to yield the maximum cleanup of New Bedford Harbor with available funding.
Specific services Lally LLC conducted in support of the Lower Harbor Confined Aquatic Disposal (CAD) Cells as requested by USEPA included;
- Analyze Bathymetric Survey Data, Geotechnical Data, Dredged Material Placement History and conducted Consolidation Modeling for future Confined Aquatic Disposal of Upper Harbor sediments.
- Conduct Geostatistical Analysis (Kriging) to delineate contaminant concentrations and develop mapping products for offsite vs. CAD cell management.
- Provide Planning and Design Guidance to Government and RAC Contractor team for Precision Mechanical Dredging of the site with respect to CAD Cell Management.
- Develop 3D Models of LHCC CAD Cells, plan views and cross sections.
- Conceive and develop Preliminary Design of Access Channel Confinement Berm as part of a CAD Cell Closure Plan.
- Develop CAD Cell Management Plans, Drawing sets, and Volume Capacity calculations.
- Evaluate Slope Stability along and between LHCC cells. Provide Scow Operations Guidance to achieve improved controlled placement of dredged material, in order to optimize volume capacity, maintain slope stability, and avoid loss of sediment outside of CAD Cells. Provide guidance on barge placement tracking parameters.
- Apply USACE-ERDC Dredged Material FATE models for LHCC Planning and Management.
- Conceive and design CAD Cell Separation Sill for dredge material management within LHCC CAD cell complex. Developed drawings, sill alignment, points file and collaborate with RAC Contractor on construction.
- Perform Numerical Modeling for various Slope Stability, Angle of Repose and Dredged Material Transport analyses.
- Travel to NBHSS regularly to support precision mechanical dredging and LHCC dredged material placement management.
- Analyze progress bathymetric survey data, fill placements, material movement, and make recommendations for barge placements.
- Maintain ongoing update surfaces of LHCC Phase I and Phase II CAD cells employing progress bathymetric surveys. Update volume capacities for management planning with USACE/USEPA, RAC Contractor and Port of New Bedford.
- Review Access Channel Confinement Berm Design with City of New Bedford, Port of New Bedford, and their consultant team for final design on behalf of USEPA.
- Coordinate with Port of New Bedford and their consultants on CAD Cell No. 4 project construction, and protection of USEPA’s containment berm and LHCC dredge material confinement.
Related Projects
Services Provided
Field Investigations
Consolidation Modeling
Geostatistical Analysis
Confinement Berm Design
Sill Design
CAD Cell Management
Slope Stability Modeling
Construction Oversight
Stakeholder, Contractor and Consultant Partnering
Location
Massachusetts, USA
Period
2018 – 2020
Over our many years of work for the USACE on the New Bedford Harbor Superfund Site, and under every eligible contract, including this one, Lally Consulting LLC has received the highest overall Contractor Performance Assessment Reporting Systems (CPARS) rating of Exceptional.
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.