Santa Rosa Aqueduct Seismic Upgrade Project
Background:
In 2008 the Sonoma County Water Agency (Water Agency) conducted a natural hazard assessment for its water transmission system. From the assessment, a Local Hazard Mitigation Plan (Mitigation Plan) was adopted. The goal of the 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 Mitigation Plan to secure the Santa Rosa Aqueduct near the Rodgers Creek Fault in Sonoma Avenue against fault rupture during an earthquake and provide safe, reliable water supply. The existing pipeline was built in 1959 and studies conclude that it could fail if a magnitude 7.0 earthquake on the Rodgers Creek fault were to occur. To ensure reliable water supply service after such an earthquake, the Water Agency has determined that a new, more flexible pipeline that parallels the existing pipeline is needed. The new pipeline would bypass and replace the existing pipeline. The $1.8 million Project is being funded by a $1.3 million Federal Emergency Management Agency Hazard Mitigation Grant and the remainder by the Water Agency’s water transmission budget.
The Project includes:
- Installing 2,000 linear feet of a 36” 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 Brookwood Avenue and Bobelaine Drive in Santa Rosa, CA.
- The new 36-inch diameter pipeline will be designed to flex in the event of a fault rupture and offset 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 grade to facilitate repairs, if needed.
About the Santa Rosa Aqueduct:
The Santa Rosa Aqueduct 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 Water Agency manages and maintains a water transmission system that provides naturally filtered Russian River water to nine cities and special districts that in turn delivers drinking water to more than 600,000 residents in portions of Sonoma and Marin counties. The City of Santa Rosa receives a majority of its drinking water from the Water Agency through the Santa Rosa Aqueduct.
Construction schedule:
Spring/fall 2011: Subsurface explorations to locate fault strands took place in June. Minor preparation activities, such as detecting underground utility lines, took place in October and November
Spring 2012: Bids for construction services will be released. Water Agency Board of Directors will review and approve a contractor to begin construction preparations
Winter 2013: Major construction activities are expected to begin – possibly as early as January 2013. Construction activities will include trenching in Sonoma Avenue’s westbound lane between Doyle Park Drive and Doctors Park Drive in Santa Rosa, CA. Construction activities are expected to last about three months with final completion in August 2013. Traffic delays due to construction activities will be limited to Monday through Friday between the hours of 8:30 a.m. and 4:30 p.m.
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 sherwood@scwa.ca.gov