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Never Eliminate Public Advice: the story of the Hoover Dam Bypass

Built during the Great Depression to provide power and irrigation to growing Western communities, the Hoover Dam is one of our country’s most recognizable landmarks.

Less than half a mile downstream lies another marvel of modern engineering: the Hoover Dam Bypass. Opened in 2010, the Hoover Dam Bypass rises some 900 feet above the Colorado River between Nevada and Arizona. Its arch, curving downward on either side, supports the four-lane roadway on top. It took almost five years to build, coming together section by section from either side.

The Federal Highway Administration (FHWA) originally developed the 3.5-mile Hoover Dam Bypass project, stretching from Clark County, Nevada across the Colorado River to Mojave County, Arizona to address increased congestion at the Hoover Dam crossing. Each day, thousands of visitors converge upon the Hoover Dam, eager to peek down at the canyon floor hundreds of feet below, gaze out at massive Lake Meade, and learn more about the dam’s massive hydroelectric turbines that feed electricity to power-hungry Las Vegas, Los Angeles, and San Diego.

However, after receiving feedback from local communities – a process mandated by the National Environmental Policy Act (NEPA) – it quickly became apparent that the project’s original Environmental Impact Statement (EIS) was inadequate. Project manager Dave Zanetell, whose team was considered a leader in environmentally responsible highway projects, admitted as much, stating that the FHWA had “grossly underestimated some of the alternatives and too quickly dismissed them.” 

Armed with this local stakeholder feedback, Zanetell’s team went back to the drawing board. In its final form, the bypass, which opened in October 2012, runs closer to developed areas instead of cutting through pristine corridors; it also includes accommodations such as sidewalks, pedestrian facilities, and parking to enable pedestrian access not included in the original design.

This model process of decision-making, including the public hearings that ultimately resulted in substantive changes to the final design of the Hoover Dam Bypass, would not have been possible without the National Environmental Policy Act (NEPA).

“Oftentimes the public is a huge influence on the project. NEPA is certainly the foundation for public participation,” said Zanetell following completion of the project. “We don’t look at it as a burden; it is something we relish.”

NEPA is one of the only laws allowing for public input in decisions that affect the health and safety of their communities. It is a vital law that gives the public the right to know and comment on how projects may impact the environment and their local communities. As such, undermining NEPA would have the effect of limiting public input and transferring decision-making power from local communities to bureaucrats in Washington, DC.


[1] “Record of Decision: US 93 Hoover Dam Bypass Project.” U.S. Federal Highway Administration. March, 2001. Available at: 

[2] “Final Environmental Impact Statement and Section 4(f) Evaluation for US 93 Hoover Dam Bypass Project.” U.S. Federal Highway Administration. January, 2001. Available at: 


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