East Dam is one of three dams constructed for the Metropolitan Water District of Southern California’s Eastside Reservoir project. The reservoir doubles Southern California’s surface storage capacity and provides a six-month emergency supply of water to nearly 16 million residents in the event of an earthquake or drought.
The 2.1-mile East Dam, constructed by a Kiewit-led joint venture, is the longest of the three dams. It measures 180 feet high, 1,200 feet wide at the base and 40 feet wide at the top. Before embankment of the dam could begin, more than 18 million cubic yards of alluvium had to be excavated to reach a solid bedrock foundation. The embankment required 43 million cubic yards of crushed rock. An on-site crushing plant crushed and processed over 14 million tons of rock in 20 months to supply the dam’s materials.
Kiewit’s extensive equipment resources were a major factor in the project’s success. More than 140 major pieces of equipment, including two 23-cubic-yard front shovels, twelve 200-ton mining trucks and 18 120-cubic-yard belly dump trucks, moved the nearly 73 million cubic yards of material in 650 days.