For West Contra Costa Sanitary Landfill, Incorporated
Richmond, California

Questa performed Construction Quality Assurance Engineering for the final capping of approximately 65 acres of landfill during the summers of 1996 through 2001. CQA work involved pre-construction laboratory testing of proposed cap materials, coordination with regulatory agencies, and observation and testing during construction. Questa tested field density and moisture content to verify compaction and moisture conditioning, and verified fill thickness for the foundation, barrier, and vegetative layers. Laboratory testing of the soils used as cap materials included permeability, maximum dry density, optimum moisture content, particle size analysis, and Atterberg limits. Questa also managed a database of field and laboratory testing results and presented the data in a final summary report.