The 242-mile Colorado River Aqueduct (CRA) was born out of plummeting groundwater levels and an overdraft that was approaching 200,000 acre-feet/year. Planning for an aqueduct from the river involved the top engineers of the day. Survey crews mapped 24,000 square miles of mostly desert territory, creating a list of 65 possible routes. One of the nation's largest public works projects, the CRA spurred development of the Metropolitan Water District of Southern California, which to this day is the largest regional water agency in the country. The project employed 35,000 men, who labored 24/7 in grueling Mojave Desert heat, erecting four dams and five pumping plants, blasting 90-plus miles of tunnels and constructing 150 miles of canals, siphons, conduit and pipelines. Daunting challenges included the 13-mile San Jacinto Tunnel, which some considered impossible. Planned to accommodate several decades of growth, the project was completed within its $220 million budget, and included the region's first large-scale water treatment plant and a two-county distribution system Deliveries began in June 1941, and helped support the World War II defense industry. It was the 1930s equivalent of a moon shot.
