To ensure neither an earthquake nor climate change cuts off drinking water to the 15 million residents in its service territory, the Metropolitan Water District of Southern California dug under mountains and along the San Andreas Fault to build a 44-mile inland feeder that conveys state aqueduct water to a recently completed manmade lake. Two 12-foot-diameter tunnels convey 1,000 cfs (cubic feet/second), a combined length of 9.6 miles.
The $500 million arrowhead tunnels project is one of five finalists vying for the American Society of Civil Engineers' (ASCE) Outstanding Civil Engineering Achievement Award, engineering's most prestigious international honor.
The other four finalists are: Concordia University Wisconsin, Mequon's lakeshore environmental enhancement (transformed 2,700 feet of severely eroded bluff into combined recreational space and outdoor classroom); in Seattle, Sound Transit's Beacon Hill underground mass transit station and tunnels, for which construction required North America's largest and deepest soft ground sequential excavation; Sutong Bridge — the world's longest cable-stayed bridge — in Jiangsu province and Suzhou and Nantong cities, People's Republic of China; and the Utah State Capitol Building in Salt Lake City, which was renovated to “float” up 2 feet in any direction during an earthquake.
The winner will be announced in March.