Grant Butte Reservoir and Pipeline Project

  • The City has secured federal funding to seismically retrofit Grant Butte Reservoir and pipeline to withstand a large earthquake. 

    Grant Butte Reservoir is Gresham’s most important emergency water supply, with the capacity to serve 66% of the city’s residents in addition to nearby medical facilities.

    • Project Description
    • Project Background
    • Project Funding
    • Contact
    Project Description

    Project timeline

    • Design 2018
    • Construction 2019-2020 

    Work will include 

    This project will help ensure the City has dependable water in the event of a major earthquake. The work is not expected to impact water service to residents. 

    • Lowering the elevation of the reservoir to prevent its roof from cracking.
    • Constructing additional seismic cables to strengthen the tank wall.
    • Adding additional cables to help resist the forces generated during an earthquake.
    • Constructing additional circumferential strand wrapping to increase hoop strength. This helps prevent corrosion if the reservoir is partially buried.
    • Constructing connections between existing column bases and concrete slab floor.
    • Securing floor grating with clips.
    • Bracing the inlet pipe.
    • Installing a seismic isolation valve.
    • Installing flexible pipe and connections.

     

    Project Background

    The Pacific Northwest is home to the Cascadia subduction zone, a 600-mile fault capable of producing   another great subduction earthquake. We don’t know how soon, how large, and how destructive that earthquake will be. We do know preparing for the “big one” is critical to our community.

    • The Oregon State legislature directed the Seismic Safety Policy Advisory Commission to lead a planning effort to better prepare Oregon for a large earthquake. 
    • In 2013, the Oregon legislature adopted the Oregon Resilience Plan. The plan identifies steps needed to minimize gaps in key services.
    • In 2016, The City of Gresham completed a Water Seismic Resilience Plan to identify key resources that may be impacted in a large earthquake. 
    • The Water Seismic Resilience Plan identified the Grant Butte Reservoir and associated piping in an area of high probability for earthquake induced landslides.  

    Resources

      

    Project Funding
    • The City secured a $2.2 million grant from the Federal Emergency Management Agency (FEMA).
    • FEMA will cover 75% of the project cost and the City will cover the remaining.

     

    Contact

    For more information about the project, contact Jason Branstetter at 503-618-2525.

    • Grant Butte Reservoir

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