The potential removal of Hoover Dam, a concrete wall over 700 feet high in Black Canyon, about 30 miles southeast of Las Vegas, would have far-reaching consequences for the Colorado River system and the region it serves. Behind the dam lies Lake Mead, the nation's largest reservoir, which supplies approximately 25 million people and vital farmland. Its drainage would lead to significant changes in water delivery, power generation, and the environment from Nevada to Mexico.
Southern Nevada, which draws about 90 percent of its water supply from the Colorado River, primarily through Lake Mead, would face immediate challenges. The region's newest intake system, designed to connect to a tunnel beneath the lake, includes a pumping station capable of withdrawals below the reservoir's 895-foot "dead pool" elevation. However, with the reservoir drained, a much narrower river channel would form, potentially leaving existing intake infrastructure above or away from the new water flow. Consequently, Southern Nevada would need a replacement or substantially redesigned water delivery system, or another dependable supply, before any dam removal.
The hydroelectric powerplant at Hoover Dam would cease operations if the dam were removed and Lake Mead drained. The plant, which houses seventeen main turbines, nine on the Arizona side and eight on the Nevada side, relies on the height difference between Lake Mead and the river below to generate electricity. With a nameplate capacity of about 2,080 megawatts, Hoover Dam's output currently serves the City of Los Angeles, the Colorado River Commission of Nevada, tribal interests, and irrigation districts, all of whom would require replacement power.
Downstream water management would also be significantly affected. Davis Dam, located 67 river miles below Hoover Dam near Laughlin and Bullhead City, and Parker Dam, which holds Lake Havasu, would remain in place. However, without Lake Mead's massive storage capacity—which far exceeds the combined capacity of Lake Mohave (1.8 million acre-feet) and Lake Havasu (648,000 acre-feet)—operators would have less ability to retain wet-year runoff or manage large inflows. This would make water deliveries for areas like Phoenix and the Los Angeles region more directly dependent on upstream releases and tributary flows.
Sediment management would become a major concern. Lake Mead currently allows much of the incoming sediment to settle. A complete drawdown would expose thick deposits accumulated since 1935, and the Colorado River would begin cutting a new channel through these materials, leading to ongoing erosion. Treatment facilities could experience increased sediment in their received water, and turbid water could potentially deposit material in Lake Mohave. Any removal plan would need to control sediment releases alongside water releases to manage post-drainage erosion.
The landscape of the drained Lake Mead basin would transform dramatically. Broad bays would be replaced by flowing channels and exposed ground, which would be either rocky or covered in accumulated sediment. Lake-based marinas would lose their function, and access roads would end above a changing river corridor. While the removal would eliminate a fish barrier at Black Canyon, potentially creating additional river habitat, it would also alter critical spawning and rearing areas for native razorback suckers, whose recovery would still depend on suitable flows and predator management.
Evaporation losses from the vast surface of Lake Mead would be reduced as a narrower river replaced much of the open water. However, this would not increase snowmelt entering the Colorado River Basin. For far downstream users, including farms and cities before the river reaches Mexico's delta, diversions would continue. Keeping additional water in the channel for these areas would necessitate changes in how water is allocated and released. The Las Vegas Bay area, where highly treated wastewater is returned to the Colorado River system via Las Vegas Wash, would also need to adapt to a changed receiving water body, requiring adjustments for replacement drinking-water intakes. Glen Canyon Dam, upstream of Hoover, would continue to provide upstream controls on the river's flows and sediment supply.
