MWH Constructors, Inc.

Scope Of Work

MWH Constructors was selected by the City of San Diego to provide third-party construction management, monitoring, administration and inspection services for the Miramar Water Treatment Plant (WTP) Upgrade and Expansion. The $180M project consisted of six elements: two early start improvement phases followed by four construction contracts. Phase I of the early start improvements consisted of initial project components of the WTP perimeter to accommodate the upgrade and expansion. This included a 70-ft-deep, 1,600-ft-long, 84-in-diameter pipeline tunnel that crossed beneath San Diego  Water Authority (SDCWA) aqueducts, 54-, 48-, and 36-in pipelines, a valve vault structure and initial improvements to the existing Miramar Lake raw water pump station.

Phase II of the early start improvements included an 84-in treated water pipeline, a 90-in raw water pipeline, new connections to the SDCWA aqueducts, further improvements to the raw water pump station and improvements to the Miramar Lake recreation . The final phases expanded the existing WTP capacity from 140 to 215-mgd, and included a deaeration basin, rapid mix facility, ozone system, 12 new filters, two new flocculation and sedimentation basins, new chemical feed system and a new administration building. The facility also included a tunnel under an existing flocculation sedimentation basin for a 72-in treated water pipeline.

One million-man hours and over nine years of construction successfully completed with only one single lost time accident