A Bolder Damn Bridge
Image by Caveman Chuck Coker
This is the new Boulder Dam Bridge being built across the Colorado River. It spans Black Canyon and the Colorado River about 1,500 feet (457 meters) south of Boulder Dam. The bridge will connect Nevada and Arizona and carry a re-aligned U.S. Route 93. The bridge should be completed by September 2010 and open to the public in November 2010. So far, it is on schedule.
What’s in a name? The Boulder Canyon Project Act of 1928 does not provide a name for the dam. Through common usage it was named Boulder Dam at the beginning of the project. On September 17, 1930, President Hoover’s Secretary of the Interior, Ray Lyman Wilbur, renamed it Hoover Dam. On May 8, 1933, newly-elected President Roosevelt’s Secretary of the Interior, Harold Ickes, renamed it Boulder Dam. On April 30, 1947, President Harry S. Truman renamed it Hoover Dam.
When Boulder Dam was completed in 1936, it was both the world’s largest hydroelectric power generating station and the world’s largest concrete structure. The dam was listed on the National Register of Historic Places in 1981 and was designated a National Historic Landmark in 1985.
A popular story says that the first person to die in the construction of the dam was J. G. Tierney, a surveyor who drowned while looking for an ideal spot for the dam. Coincidentally, his son, Patrick W. Tierney, was the last man to die working on the dam, 13 years later, to the day.
As of January 2010, about 14,000 vehicles cross Boulder Dam each day.
The total gross power rating for the hydroelectric power plant is about 2080 megawatts.
The bridge’s official name is the "Mike O’Callaghan-Pat Tillman Memorial Bridge." Mike O’Callaghan was the Governor of Nevada from 1971 to 1979. He died in 2004 at 74 years of age. Pat Tillman graduated with honors from ASU and played professional football for the Arizona Cardinals before joining the Army. He was killed by "friendly fire" in the mountains of Afghanistan in 2004.
The 1,060-foot (323-meter) twin-rib concrete arch of the bridge was completed in December 2009. The final sections of the arch were connected on August 10, 2009. Removal of the supporting cable system was completed on August 27, 2009, and the arch is now self-supporting and free standing. The total length of the bridge will be 1,900 feet (579 meters). The bridge deck and sidewalk will be approximately 900 feet (274 meters) above the Colorado River.
The Hoover Dam Bypass Project is a 3.5-mile (5.6-kilometer) corridor beginning at approximately milepost 2.2 (3.5 km) in Clark County, Nevada and crossing the Colorado River approximately 1,500 feet (457 meters) downstream of the Hoover Dam, then terminating in Mohave County, Arizona near milepost 1.7 (2.7 km) on U.S. 93.
The design and construction budget is 0 million. The Colorado River Bridge construction portion of that budget is 4 million.
The present route of U.S. Route 93 uses the top of Boulder Dam to cross the Colorado River. U.S. Route 93 is the major transportation corridor between the states of Arizona, Nevada, and Utah. It is also on the North American Free Trade Agreement (NAFTA) route between Mexico and Canada. In 1995, the National Highway System Designation Act identified U.S. Route 93 as a high priority corridor. The traffic congestion caused by the inadequacy of the existing highway across the dam imposes a serious economic burden on the states of Arizona, Nevada, and Utah.
The traffic volumes, combined with the sharp curves on U.S. Route 93 in the vicinity of Boulder Dam, create a potentially dangerous situation. A major catastrophe could occur, involving innocent bystanders, millions of dollars in property damage to the dam and its facilities, contamination of the waters of Lake Mead or the Colorado River, and interruption of the power and water supply for people in the Southwest.
By developing an alternate crossing of the river near Boulder Dam, through-vehicle and truck traffic would be removed from the top of the dam. This new route would eliminate the problems with the existing roadway—sharp turns, narrow roadways, inadequate shoulders, poor sight distance, and low travel speeds.
The purpose of the project is to accomplish the following objectives:
• Minimize the potential for pedestrian-vehicle accidents on the dam crest and on the
Nevada and Arizona approaches to the dam.
• Remove a major bottleneck to interstate and international commerce and travel in the
west by reducing traffic congestion and accidents in this segment of the major
commercial route between Phoenix and Las Vegas.
• Replace an inadequate highway river crossing with a new crossing that meets current
roadway design criteria and improves through-vehicle and truck traffic capacity on
U.S. 93 at the dam.
• Reduce travel time in the dam vicinity.
• Protect Hoover Dam employees, visitors, equipment, power generation capabilities
and Colorado River waters, while enhancing the visitors’ experience at Hoover Dam by:
• Safeguarding dam and power plant facilities and the waters of Lake Mead and the
Colorado River from hazardous spills or explosions.
• Protecting the dam and power plant facilities from interruptions in electricity and
• Providing improved conditions for operating and maintaining Hoover Dam facilities.
The Bureau of Reclamation’s Lower Colorado Region – Hoover Dam website can be found at www.usbr.gov/lc/hooverdam/.