Landfill Cover System Design and Closure Plan; Marine Corps Air Station Iwakuni, Japan

Project Description: Designed an engineered cover system and prepared closure/post-closure plans for Marine Corps Air Station Iwakuni’s (MCASI) 33-acre landfill, one of the last active DoD landfills in Japan. The work was performed in accordance with the Japan Environmental Governing Standards (JEGS) and USACE guidance documents.

  • Geotechnical Investigation
    • Geophysical survey, 100+ soil borings, laboratory geotechnical analyses, 100+ test pits, waste characterization, and topographic surveys
    • Information gathered assisted the landfill engineers in developing viable options (feasibility study) for constructing a JEGS-compliant landfill cover system
  • Feasibility Study
    • Evaluated seven alternatives for landfill closure based on regulatory requirements (JEGS), cost, technical challenges in implementing the alternatives, and the MCASI area redevelopment plan
    • Selected alternative included on-site waste relocation, compaction, and an engineered cover designed to support light industrial use post-closure
  • Design Services
    • Produced 30%, 60%, and 100% deliverables; drawings, specifications, engineering analyses, bid documents, construction cost estimate (MCACES)
    • Slope stability, liquefaction, veneer stability, geomembrane equivalency, stormwater, soil erosion control, gas venting, access roads
  • Closure/Post-Closure Plan
    • Included closure procedures (permitting, construction, as-built topographic survey) and post-closure procedures, including inspections, maintenance, landfill gas, and groundwater monitoring, and all associated quality control and documentation; prepared in accordance with JEGS

Project Value: $1.4 million

Contracting Agency: USACE Tulsa District

Location: Marine Corps Air Station Iwakuni, Japan