Vista Village Trunk Sewer Project

Vista, California

A capacity deficiency in the City of Vista Village’s largest trunk sewer was identified as the highest priority sewer capacity project in the City’s master plan. The City prepared a preliminary design report (PDR) to identify upgrade alternatives and all options were highly challenging and impactful to the City’s most visible commercial corridor. The Vista Village Trunk Sewer Project addresses the City of Vista’s second-highest priority capacity deficiency. The existing 30-36-inch pipeline transected the most visible entry to the City, an environmentally sensitive habitat within Buena Vista Creek and the SR-78 freeway within a casing pipe installed in the 1980s.

For this project, the City retained and organized a Progressive Design-Build (PDB) solution, partnering the owner, operator, designer, contractor and advisory construction manager to greatly improve outcomes. PDB for the project increased system capacity and addressed three identified capacity improvement projects; avoided large bypass and reduced traffic impact; minimized trenchless length, risk, and cost; eliminated the need to reconstruct the sewer dump station, and detected and addressed challenging hard-rock and mixed face conditions.

Technology included pilot tube exploration borings, micro-tunneling, deep trenching, air-track perforation drilling, rock breaking, flow-through gravity bypass and live flow diversion systems, polymer concrete and epoxy spray linings. The solution avoided disturbance of environmental habitat, the existing dump station, and maintained project control by avoiding acquisitions. The parallel alignment increased capacity and added redundancy and operational flexibility.

Michael Baker International led the TC-Michael Baker Progressive Design Build (PDB) team to deliver a highly constrained project in a way that greatly exceeded expectations. Notably, the project was completed nearly $2 million below the original $17 million planning estimate and ahead of schedule. The success is a shining example of improved outcomes with PDB for highly constrained projects.