Mercer Island Decant Facility Retrofit

Herrera assisted the City of Mercer Island with retrofitting their existing decant facility. Herrera prepared a grant-winning predesign report, which included a conceptual design and itemized cost estimate. Using the predesign report, the City received a grant for $111,000 from Ecology for design and construction of the decant facility. Herrera also supported the City in identifying necessary permits and completing some permitting requirements in advance, thus garnering a higher score for the grant application. Herrera then prepared the plans, specifications, and a cost estimate for the retrofit. The design provided: 1) containment of sediment and fluid on the decant pad with perimeter barriers, 2) installation of new catch basin structures, and 3) installation of new piping to convey flows to the sanitary sewer system.

The team also provided construction management to ensure the project met specified design requirements and to provide technical oversight during construction. Herrera also prepared a Construction Quality Assurance (CQA) Plan and the Operations and Maintenance Manual for the facility.