Ninyo & Moore conducted three combined Geotechnical Evaluations and Phase I/Phase II Environmental Site Assessments at a proposed landfill redevelopment site, which included demolition of existing buildings and construction of an industrial distribution center over former gravel pits reportedly used for construction debris dumping.

Project Highlights:

• Geotechnical Evaluation
• Phase I Environmental Site Assessment
• Phase II Environmental Site Assessment
• Soil and Soil Gas Sampling
• VCUP Application
• MMS Installation Oversight

Ninyo & Moore conducted two separate rounds of soil and soil gas sampling to determine geotechnical suitability, environmental characteristics, and methane impacts at the site as directed by Adams County and the Tri-County Health Department. Methane was detected in soil gas samples during both previous sampling events and methane mitigation systems were recommended for the proposed new buildings. The Colorado Department of Public Health and Environment’s Voluntary Cleanup Program (VCUP) was recommended for the site and subsequent groundwater monitoring was requested and conducted. Domestic waste was found in small quantities in the north and east portions of the site. The site was deemed suitable for construction even though up to 30 feet of previous undocumented fill was encountered. Ninyo & Moore worked with the design team to come up with a viable solution for spread footings and a slab-on-grade floor bearing within the fill materials. A VCUP application was submitted and approved, which included a Materials Management Plan (MMP) for any required soil remediation during construction. MMP oversight was conducted during construction including the installation of a Methane Mitigation System (MMS) in accordance with the approved VCUP. As part of the overall environmental plan for the site, a sub-grade storm water detention vault was constructed. Ninyo & Moore also conducted design support and installation oversight of the storm water system, in accordance with State and local municipal guidelines. The storm water detention vault was designed and constructed to manage storm water volume and help prevent flooding and erosion in the adjacent receiving creek.

Project Details

Karis Partners

Denver, Colorado