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Submitting Firm: RH2 Engineering
Location: Lake Oswego
Client/Owner: Rivergrove Water District
Other Consultants/Key Participants: Compass Land Surveyors, Emery & Sons Construction Group LLC, GRI
Noteworthy: The Reservoir No. 3 Landslide Remediation and Seismic Upgrades project answered many of the reliability and maintenance questions for the district’s largest zone. Built in 1977, the tank site experienced a landslide shortly after being built, severely limiting access to the reservoir. The lack of critical infrastructure to efficiently take this tank offline hindered the district’s ability to perform regular operations and maintenance safely and effectively, including crucial repairs needed to ensure that the reservoir could remain in service during and after an earthquake. The project addressed these problems through a carefully orchestrated series of improvements, including: top-down soil nail slope stabilization to protect against future landslides; pump station and pipeline improvements to increase redundancy and resilience; intertie and PRV improvements to improve reliability; and reservoir foundation and mechanical improvements to improve seismic performance. These improvements also provide the district with increased operational flexibility, ensuring it can continue to provide its customers with safe, reliable drinking water.