The Former Draper King Cole Cannery site, located in Milton, Delaware, was an approximately 35-acre vegetable cannery, which has been redeveloped for mixed-use residential and commercial redevelopment. As part of the project, approximate 16 acres of buildings were demolished, including the processing plant and various warehousing facilities. Ten Bears completed a Voluntary Cleanup Program investigation of the site on behalf of the redeveloper. The RI/FS for the property generally consisted of soil, sediment, and groundwater sampling and laboratory analysis, a limited human health risk assessment and establishment of remedial action objectives, followed by a feasibility study to evaluate potential remedial alternatives, and selection of the proposed remedy. A large volume of impacted soils containing relatively immobile No. 6 Fuel Oil was contained on site, avoiding excessive off site treatment and disposal costs. A parking lot that serves portions of the commercial development caps other impaired soils that were relocated during the remedial action.
Due to similarities in site characteristics for portions of the Halby Chemical Federal Superfund and Potts Property Hazardous Substance Cleanup Act (HSCA) sites, combined with their proximity to one another, the Remedial Designs for the two sites were completed as a coordinated effort, preserving design continuity and providing design savings to the responsible parties. Ten Bears personnel continue to assist our client with navigating shifting EPA and State of Delaware program requirements for the ongoing Operations and Maintenance of the site.
Ten Bears personnel participated in this fast-track VCP project from the initial, due-diligence property assessments through remedial construction. The owner developed the property, located near downtown Wilmington, into a daycare center with below-grade parking, necessitating bulk excavation that included environmentally impacted soils. As a result, Ten Bears personnel contracted for the remedial excavation, as well as the bulk excavation for the building project.
Ten Bears personnel oversaw multiple remedial contractors and acted as liaison between DNREC and the owner. Pre-remedial site investigations identified debris fill soils that contained several heavy metals, petroleum, and PAHs. As is typical of any subsurface project, several conditions were uncovered during excavation that were not encountered by site investigation, including underground storage tanks and buried asbestos-containing materials. Based on our experience with similar projects, Ten Bears personnel had previously notified certified removal contractors to be prepared to handle such contingencies. As a result, potential production delays and associated expenses were minimized.
The City of Wilmington proposed to develop this South Wilmington site as an apartment complex to provide housing for low-income families. Previous site evaluation performed by others indicated that near-surface soils contained elevated concentrations of metals, petroleum hydrocarbons, and PAHS. Due to the client’s desire to remove impacted soils from the site while maintaining the project schedule, excavation and off-site disposal of the soils was performed as an Interim Action under the VCP. Ten Bears personnel negotiated and managed contracts with the subcontractors responsible for the remedial excavation, waste transportation and disposal, fence installation, surveying, and laboratory analysis.
Groundwater occurred at shallow depths hindering the removal of impacted soils. In addition, a geotechnical evaluation performed by others indicated that soft soils were present beneath the impacted soils on portions of the site. Therefore, Ten Bears personnel consulted geotechnical engineers to assist in developing a program for removing the impacted soils and placing backfill with minimal impacts from site groundwater to the structural stability of the on-site and imported soils.
The restoration of the site presented other design challenges. The construction plans called for additional excavations for foundation construction to be done following the restoration of the site with structural fill during site remediation. As a result, restoring the site to finished grading during remediation would result in removal and disposal of a significant quantity of the imported fill materials. Also, restoring the site to elevations to achieve a balanced cut and fill for construction would have left the site below street level prior to construction. This alternative likely would have facilitated ponding of stormwater on the site, which would have softened the placed structural fill. As an alternative, Ten Bears personnel developed temporary post-remedial surface grading to facilitate drainage toward an on-site sump. This solution provided positive drainage of the fill while eliminating the need to remove imported fill materials during construction, resulting in considerable cost savings to the property developer and a significant improvement in the structural fill upon which the foundation work could begin.
The West End Neighborhood House proposed to develop this West Wilmington site for townhomes to provide housing for low-income families. Initial due-diligence indicated that near-surface soils contained historical demolition waste with elevated concentrations of metals, petroleum hydrocarbons, and PAHs. Due to the client’s desire to remove impacted soils from the site for unrestricted use, excavation and off-site disposal of the soils was performed as remediation under the Brownfields program. Ten Bears personnel negotiated and managed contracts with the subcontractors responsible for the remedial excavation, waste transportation and disposal, fence installation, surveying, and laboratory analysis.
Ten Bears personnel provided environmental evaluation and remedial construction management services to facilitate the re-development of this Brownfield site into a mixed use, residential / commercial complex. This former lumber and coal yard was addressed under Delaware’s Voluntary Cleanup Program (VCP). The primary contaminants driving remediation were arsenic, PAHs, and petroleum in shallow site soils. Ten Bears personnel worked closely with State regulators to develop and implement a site remediation program that balanced community concerns with those of the developer and former owner. Based on the location and types of contaminants, a cover or capping system with selective removal of contaminant “hot spots” was the selected remedial alternative. Ten Bears personnel managed the remedial construction, coordinating the activities of several remedial contractors. Ten Bears personnel developed an innovative approach to capping the impacted soils to limit remedial costs. Based on the large area of impacted soils, estimated costs for capping the soils in place approached those for off-site removal. Also, requirements imposed by the State of Delaware for including a minimum of 1.5 feet of soil in any proposed cover system would have necessitated re-entering the City of Newark’s development approval process for revised grading. Our solution was to excavate the impacted soils and place them beneath the proposed building footprint. Relatively soft soils were removed from beneath the building location prior to placement and compaction of the impacted soils. The result improved the structural stability of the soils supporting the building foundations, as well as reducing overall project costs and accelerating the schedule for construction.
Ten Bears personnel developed specifications and contracted for the remedial and bulk foundation excavation for a fast-tracked, approximately $2,300,000 remedial action near downtown Newark, New Jersey. The design of the building, which covered the majority of a city block, included below-grade parking, necessitating the removal of approximately 60,000 tons of soils, including approximately 40,000 tons of environmentally regulated historical fills.
Despite time constraints, Ten Bears personnel developed a program through additional evaluation that considerably reduced the volume of excavation for off-site disposal of impacted soils providing significant cost saving to the project owner. Based on the investigation and follow-up construction monitoring, Ten Bears personnel successfully limited the excavation of regulated soils to an average depth of approximately 10 feet (from a previously estimated 25 feet). Additional soils excavated for foundation construction were reused off-site as unregulated soil fill, also at a greatly reduced cost.
To meet project schedule requirements, remedial excavation began prior to completion of building foundation design. Ten Bears personnel worked closely with the owner, construction manager, and design team to participate in design changes as the remediation proceeded. Although faced with foundation excavation depths as great as 20 feet and changing design parameters, Ten Bears personnel implemented strategies to maintain the stability of excavation sidewalls while minimizing expensive shoring, resulting in substantial cost savings to the owner. The remedial excavation was turned over to the foundation contractor on time and under budget.
Ten Bears personnel performed remedial investigation, remedial design, and remedial oversight for the closure of an abandoned poultry plant. The project involved asbestos abatement, cleanup of spills of polychlorinated biphenyls (PCBs), petroleum UST removal, disposal of containers of hazardous wastes, and building demolition, including management of materials coated with lead paint. As well as investigating the site and developing specifications for cleanup, Ten Bears personnel coordinated the activities of four separate contractors on overlapping schedules totaling less than 6 weeks. Despite the challenges presented by working in northern New England during the winter months, this $1,000,000 remedial project was completed on time and under budget.