The Mokelumne Aqueduct, some 87 miles long, consists of three large-diameter pipes,constructed in 1929, 1949, and 1963. The aqueduct carries water from the Sierra Nevada foothills to the East Bay Area, providing nearly 80% of the area's water supply.
The aqueduct underwent a seismic retrofit of support bents, expansion joints, and temperature anchors. At this location, a temperature anchor from 1929 had to be removed. GEO deployed four solar powered vibration monitors to record the energy from demolition.