Mokelumne Aqueduct Seismic Upgrade

The Mokelumne Aqueduct consists of three large-diameter pipelines of up to 87” diameter that are the sole water supply system for 1.4 million people in Northern California. A key part of EBMUD’s comprehensive Water Supply Management Program is system and supply security, and the aqueduct was identified as a vulnerable element.

GEI was hired to manage a multidisciplinary team of seismologists, geologists, geotechnical engineers, structural engineers, and cost/ repair/scheduling estimators to develop engineered alternatives for seismically upgrading nine miles of elevated pipe, five miles of buried pipe, and three river crossings. The project included: evaluating seismicity and ground response; analyzing foundations and pipeline dynamic response to earthquake shaking; assessing levees and buried pipelines at three river crossings; developing alternative structural and geotechnical solutions to identified weaknesses; estimating upgrade/repair costs and schedules; developing a permitting strategy to satisfy local, state and federal requirements; and recommending upgrade alternatives for detailed design. GEI completed the final design of the river crossings and performed construction management services.