How was the river diverted during dam construction?
The river was diverted around the damsite through four 50-foot diameter tunnels, two on each side of the river drilled through the canyon walls. The tunnels, with a total length of 15,946 feet, or about 3 miles, were excavated to 56 feet and lined with 3 feet (300,000 cubic yards) of concrete. The tunnels could carry over 200,000 cubic feet – more than 1.5 million gallons – of water per second! The river was diverted through the two Arizona tunnels on November 14, 1932.
