Santa Rosa Aqueduct Seismic Upgrade Project

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    In 2008, the Water Agency, conducted a natural hazard reliability assessment for its water transmission system. The system includes more than 90 miles of underground pipe. From the assessment, a Local Hazard Mitigation Plan (Mitigation Plan) was adopted. The goal of the Mitigation Plan is to better secure water supply facilities when natural disasters occur and seek funding opportunities from federal and state agencies to help pay for those facility upgrades.

    About the Project:

    The Santa Rosa Aqueduct Seismic Upgrade Project (Project) was identified in the Water Agency’s Local Hazard Mitigation Plan to secure the Santa Rosa Aqueduct near the Rodgers Creek Fault in Sonoma Avenue against fault rupture during an earthquake and provide a safe, reliable water supply.

    The Project includes:

    • Installing approximately 2,000 linear feet of a 36-inch diameter steel water supply pipeline on a portion of the Water Agency’s existing Santa Rosa Aqueduct pipeline where it crosses the Rodgers Creek Fault in Sonoma Avenue between Doyle Park Drive and Doctors Park Drive in Santa Rosa, CA.
    • The new 36-inch diameter pipeline will be designed to deform in the event of a fault rupture and oset due to a major seismic event.
    • Isolation valves and manifolds will be installed at each end of the new pipeline so that temporary flexible pipelines can be installed above surface to facilitate repairs, if needed.

    The Project may result in some traffic congestion and noise from heavy equipment during construction hours. We do not anticipate any disruptions to utility services, such as drinking water.

    About the Santa Rosa Aqueduct:

    The Santa Rosa Aqueduct, a major drinking water pipeline, was built in 1959 by the Water Agency to deliver naturally filtered drinking water from the Russian River to communities in portions of Sonoma and Marin counties, including the City of Santa Rosa.

    About the Sonoma County Water Agency:

    The Sonoma County Water Agency (Water Agency) is the water supply wholesaler to our region, managing and maintaining a water transmission system that provides naturally ltered Russian River water to nine cities and special districts that in turn deliver drinking water to more than 600,000 residents in portions of Sonoma and Marin counties. The City of Santa Rosa is the retail water supplier for the majority of the residents of Santa Rosa and receives a majority of its drinking water from the Water Agency through the Santa Rosa Aqueduct.

    Construction Schedule

    (Click to enlarge)Sonoma Avenue aqueduct replacement construction schedule


    Outreach Materials

    Project information and updates:

    For more information about this Project and to receive updated construction information, please call Outreach Coordinator Brad Sherwood at 547-1927 or email

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