The Agua Hedionda Lift Station (AHLS) is a large, complex, pumping plant. It conveys raw wastewater from the cities of Vista and Carlsbad to the Encina Water Pollution Control Facility (WPCF) via a gravity trunk line across the Agua Hedionda lagoon and a combination of trunk line and force main along Avenida Encinas. The lift station was previously constructed and partially operational. Installation included force main and gravity sewer piping, an influent grinder system and a dry pit/trench-style wet well lift station, consisting of four “lift pumps” (7 MGD capacity each) and four force main pumps (5.25 MGD capacity each). The lift station is jointly owned by the cities of Vista and Carlsbad and is operated by the Encina Water Authority.

Due to undisclosed project issues, the original contractor was no longer available to complete the final project work. The City of Vista pursued an alternative approach to complete the unfinished AHLS work. Completion of the project included relocation of two existing standby diesel engine pumps, demolition of the pre-existing onsite lift station and appurtenances, earthwork, final grading, paving, landscaping, and stormwater pollution prevention. The City had decided to utilize the progressive design-build delivery (PDB) model to complete the AHLS. By using the collaborative PDB delivery model, the City of Vista, TC Construction, and Michael Baker International, completed the scope of work within the available budget and streamlined schedules.

The AHLS Completion Project included services required from the PDB including pre-construction, construction, and operations start-up of the project. A guaranteed maximum price (GMP) was developed based on all management, supervision, labor, services, equipment, tools, supplies, and other items required for a comprehensive design and construction program.