Wilmington, Delaware

Project at a Glance:

• Investigation and construction supervision of former landfill located along the Brandywine Creek in Wilmington, Delaware.
• Whitman conducted stream studies, designed a cap and drainage system, and provided operations and maintenance of the completed facility.

The former Container Corporation of America (CCA) site consists of an abandoned quarry used for the disposal of solid waste materials from the manufacture of corrugated paper. The former CCA mill was located across the Brandywine Creek from the historic Bancroft & Sons textile mill (see photo). The mill, located approximately 1,500 feet downstream from the quarry, was converted into the Brandywine Condominium Complex (not shown).

Whitman, under Delaware’s Division of Natural Resources and Environmental Conservation (DNREC) supervision, conducted a Remedial Investigation of the site in 1993. The Remedial Investigation included pre-existing data evaluation, geophysical survey, test pit excavation, and soil, sediment, and surface water sampling.

The analytical results of sediment and surface water sampling revealed that existing environmental conditions at the former CCA site did not appear to pose any threat to the surface water quality of the Brandywine Creek.

However, contamination was found in the soil. The soil was contaminated with polyaromatic hydrocarbons, polychlorinated biphenyls, and heavy metals.

DNREC determined that the presumptive remedy for municipal landfill sites would permit existing passive land use activities, such as nature trail, right-of-way, parkland, and pedestrian paths.

Whitman conducted remedial action construction at the former CCA site from August 1997 through December 1997.

Construction activities were coordinated on a daily basis between Whitman, the DNREC project manager, DNREC Sediment and Stormwater Construction Reviewer, and the contractor to facilitate completion of the work within the projected schedule and budget.

The presumptive remedy included the installation of a foundation layer and low-permeability layer, overlain by a topsoil layer capable of supporting vegetation. The remedy also required the installation of stormwater drainage facilities and final grading of the site.

At the completion of the project, Whitman procured additional erosion protection to minimize the potential for damage to the landfill cap during the winter and until the vegetative cover was firmly established.

Views of the site after completion of the project.

Aerial view of site during the construction of the cap.