36-inch Transmission Main Replacement Project

Background & Objectives

The 36-inch transmission main is a critical component of Sweetwater Authority’s water distribution system. The pipeline is a key transmission facility connecting the Authority’s primary water source at Sweetwater Reservoir/Perdue Water Treatment Plant to the distribution system in Bonita Valley and western Chula Vista. The most critical sections of the transmission main, some of which have been in service for nearly 100 years, have reached the end of their service life and will be replaced to maintain service reliability.

36-inch transmission main pipeline

Project Overview

The 36-inch Transmission Main Replacement Project involves:

  • Installation of approximately 3.5 miles of new transmission main
    • 15,000 feet of 36-inch welded steel pipeline
    • 3,100 feet of 48-inch welded steel pipeline
  • Abandonment of approximately three miles of existing transmission main
  • Realignment of pipe segments into improved right-of-way and away from less accessible areas including  the Bonita Golf Course and an easement within a condominium complex

Temporary Impacts

  • Traffic control
    • Construction will avoid peak traffic times at critical intersections
  • Temporary trail access impacts near the Bonita Golf Course and the Chula Vista Golf Course
    • Construction schedule will avoid high trail usage season and limit impacts to daytime construction hours
  • Installation of pipeline segment at the Chula Vista Golf Course and Bonita-Sunnyside Library parking lot

Estimated Timeline

  • April 2019 - Construction contract awarded
  • June 2019 - Construction starts with fabrication of welded steel pipe
  • November 2019 – Contractor mobilizes to first segment (Bonita Golf Course)
  • December 2020 - Construction completed

Project Location

All pipeline replaced during this project is located within the Bonita Valley. See detailed project map.