Case Study

Landfill Cover Design-Build (US)

The Army Environmental Command (AEC) closed the Site 1 Landfill at the Marine Ocean Terminal in Concord, CA. It was historically formed by pushing waste out into the adjacent tidal marsh; resulting in submerged waste and portions of the waste mass within the tidal fluctuation zone. The landfill is underlain by San Francisco Bay Mud, which can experience appreciable settlement under loading


Concord, CA


American Integrated Services Army Environmental Command

Project Objectives:

SLR was part of a design built team (with AIS) that aimed to develop an innovative design that relies on a partially exposed geomembrane to minimize surcharge loads in the tidal fluctuation zone and a multilayer prescriptive cover over the balance of the landfill, designed to retain positive drainage under anticipated future settlements.

This design eliminated additional encroachment in the wetland and the cover was built with the fill already imported on site thereby reducing the total construction cost and minimizing disruption in the community and the base.

Our Role

  • Design Services
    • grading plan
      • work with soil in place (no import)
      • no excavation
    • cover system – use bituminous geomembrane
    • static and seismic stability,
    • consolidation and deformation analyses
    • stormwater management system
    • soil loss evaluations and erosion control system.
  • Site geotechnical investigation.
    • prepared an Army approved work plan to address UXO hazards.
    • drilling and sampling
    • laboratory testing.
  • Preparation of documents:
    • Construction: drawings, Technical Specifications CQA plans
    • Regulatory: Closure and Post-Closure Maintenance Plan
  • Meetings with the stakeholders to present the design and gain approval.
  • Construction Quality Assurance Services
    • Throughout construction with SLR personnel