Stormwater Management – Closure Design and Construction, Fresh Kills Landfill, New York City Department of Sanitation
SCS Engineers provided a full range of engineering, construction support and scientific services associated with filling and closing the 16,000 ton-per-day Fresh Kills Landfill, the world’s largest landfill.
The City of New York took a progressive approach to complying with New York State Department of Environmental Conservation (NYSDEC) Part 360 regulations and the NYSDEC Consent Orders, and closed two of the four landfill mounds with the intent of implementing end-use plans that will enhance the region.
Our services included site investigations, conceptual and final designs for phased closure of the mounds, capping, stormwater management, landscaping, wetlands remediation, shoreline improvements and LFG controls and monitoring.
The construction-related services included:
Final Cover System Design: Created final cover system design, which included geomembrane and clay barrier materials, geotechnical testing, and slope stability analysis. The final thickness and properties of the vegetative layer were based on root penetration and native plant tests, as well as compatibility with the drainage layer over the barrier material.
Drainage Plans: Designed the stormwater management structures, including swales, downchutes, and sediment basins. Due to the size and geometry of the site, SCS developed a unique downchute system that consisted of buried pipes to convey stormwater off the 200 foot high sideslopes. In addition, since each of the landfill mounds was bounded by wetlands and surface waters, wetlands remediation was included in the sediment basin and outfall designs.
Regulatory Activities: On behalf of our client, we had extensive interaction with the NYSDEC. Each Consent Order Deliverable was negotiated, reviewed and approved by the NYSDEC, which allowed the project to progress to the bid document and construction phases.
Bid Documents: Prepared construction drawings, specifications and contract documents. The construction value for closure of the 108- and 120-acre landfill mounds was estimated to exceed $40 million. The scope of the construction documents included grading plans, cover system components, access roads, stormwater management facilities, LFG cutoff trenches and collection system, wetlands remediation and revegetation.
QA/QC Plans: Developed a QA/QC manual for the final cover system construction.
Construction Management: SCS opened an office staffed with full-time professionals and technicians to serve the projects. SCS’s construction management team consisted of a resident engineer and three to seven engineers and CQA technicians for each landfill mound. Our resident engineers were responsible for approving construction work, tracking quantities, reviewing and commenting on progress payment requests, negotiating contract change orders, coordinating with the on-site NYSDEC staff and the client, coordinating schedules, and related construction issues.
During the first construction season, approximately 60 acres of the cover system were constructed on Section 3/4, and 80 acres were construction on Section 2/8 (pictured). The balance of the work was completed the next year on both Sections.
The number of engineers and CQA technicians varied in accordance with the type and level of construction activities. Because of the extent of QA and QC testing and the size of the landfills, interim certification reports were prepared and submitted to the client and the NYSDEC as construction progressed.