Lake Mead, located on the Colorado River along the Nevada-Arizona border, is the largest reservoir in the United States. It provides water to around 25 million people across seven states in the Southwest. However, due to overallocation of the Colorado River’s water, drought, and climate change, Lake Mead has declined dramatically since 2000. As of November 2022, Lake Mead is at just 28% of its full capacity. If Lake Mead continues to decline, it could potentially dry up completely. This would have enormous repercussions across the region.
What is causing Lake Mead’s water levels to drop?
There are three key factors leading to the decline of Lake Mead:
- Overallocation of the Colorado River – More water has been allocated to states and Mexico from the Colorado River than the river actually provides each year. This imbalance has depleted reservoirs like Lake Mead over time.
- Drought – Much of the Southwest has been in an on-and-off drought for over 20 years. Dry conditions reduce runoff and water flows into Lake Mead.
- Climate change – Rising temperatures increase evaporation and reduce snowpack, further limiting the Colorado River’s flows.
These factors have combined to take a major toll on Lake Mead. Since 2000, the reservoir’s water level has dropped around 140 feet.
What water level is considered “dead pool”?
The term “dead pool” refers to the point when Lake Mead’s water level drops so low that water can no longer flow downstream from the reservoir or pass over the spillway. Engineers determine that Lake Mead would reach dead pool at around 895 feet above sea level.
As of November 2022, Lake Mead’s water level is around 1,044 feet. So the reservoir has already declined 149 feet but has another 150+ feet to go before reaching dead pool status.
What happens when Lake Mead hits dead pool?
If Lake Mead continues to decline and eventually hits dead pool at 895 feet above sea level, the consequences would be very severe:
- No water would flow from Lake Mead downstream to Lake Mohave near Laughlin, Nevada. This would leave Lake Mohave totally reliant on its own inflows.
- Water could not be pumped from Lake Mead to meet water delivery obligations to Arizona, California, and Mexico under the Colorado River Compact.
- Las Vegas would lose its main water source, which provides 90% of the city’s supply. Las Vegas would struggle to find enough replacement water.
- Hydroelectric power generation at Hoover Dam would cease because intakes would be left high and dry.
- The remaining shallow pools of water left in Lake Mead would likely be unusable. Water quality would deteriorate due to high salinity and algae blooms.
Could Las Vegas run out of water if Lake Mead dries up?
Las Vegas relies on Lake Mead for about 90% of its water supply. If Lake Mead hits dead pool, the city would lose its main water source. However, Las Vegas would not completely run out of water.
The Southern Nevada Water Authority has prepared for the possibility of Lake Mead drying up. It has built infrastructure to allow water to be pumped to Las Vegas from further down the Colorado River, below Lake Mohave. Pipelines and pumping stations can bring this “river water” back to the city.
Las Vegas has also invested in water recycling systems. Treated wastewater can be purified at advanced treatment facilities and reused for non-potable purposes like irrigation.
Additionally, Nevada has groundwater aquifers that Las Vegas could tap into as a supplemental source. Groundwater would need to be used carefully to avoid depletion.
So Las Vegas would have severe challenges finding replacement water and costs would greatly increase. But the city would likely avoid catastrophic failure of water supplies. Conservation and rationing would also help stretch available water further.
What problems would a dried up Lake Mead cause for hydropower?
If Lake Mead dries up, it would significantly impact hydropower from Hoover Dam. Hoover Dam’s 17 main turbines rely on Lake Mead to provide the water that powers them.
Hoover Dam generates over 4 billion kilowatt-hours of electricity each year. This resource provides excess power to utilities across Nevada, Arizona, and California. Hoover Dam’s hydropower capacity would decline as the lake declines, before being eliminated completely at dead pool levels.
The loss of Hoover Dam’s electricity generation would remove a vital clean energy resource from the region. Utilities would have to replace it with other sources like natural gas. Power costs would likely increase for many customers.
Additionally, Hoover Dam’s visitors center, elevators, and lighting all require power from the dam. A dried up Lake Mead could force closures and impact tourism at the iconic landmark. Backup generators could provide minimal power, but operations would be much more limited.
What other reservoirs and lakes could eventually be impacted?
| Reservoir | River |
|---|---|
| Lake Powell | Colorado River |
| Lake Shasta | Sacramento River |
| Lake Oroville | Feather River |
| Lake Folsom | American River |
If the drought on the Colorado River continues and water levels keep dropping, Lake Powell could face risks similar to Lake Mead. Lake Powell is upstream from Lake Mead, and its flows help replenish Lake Mead. But Lake Powell is also shrinking from the drought. It is currently at just 28% of capacity, raising concerns it could approach dead pool status around 3,370 feet above sea level.
Further, reservoirs in California that supply water to Central Valley agriculture and Southern California cities are also under drought stress:
- Lake Shasta and Lake Oroville on the Sacramento and Feather Rivers – These reservoirs that feed the State Water Project have fallen to around 30% of average levels for late fall.
- Lake Folsom on the American River – This Sacramento/San Joaquin Delta reservoir is at just 22% of capacity.
California’s reservoirs are interconnected as part of the state’s complex water delivery network. Declines in one reservoir put pressure on supplies elsewhere. Drought and climate change impacts could eventually cause Dead Pool conditions in these lakes if the current drought persists.
Would the dried lakebed be usable?
If Lake Mead fully dried up, it would expose over 130,000 acres of lakebed. This muddy land, covered in sediment and minerals built up from decades underwater, would initially not be appropriate for much use.
With time, the exposed lakebed soils could be engineered and managed to support some new uses. However, large-scale commercial or residential development would still be very challenging and expensive. Issues would include:
- Poor soil quality – The dried lakebed muds contain high salt content and minerals unsuitable for many plants.
- Dust – Exposed fine silt sediments could blow up in high winds, creating dust storm hazards.
- Hydrology changes – With the lake gone, area groundwater flows and conditions would shift.
- Recreation loss – The dried lake bottom would no longer support boating, fishing or other water sports.
It would likely require decades of soil treatments, grading, and slowly working in vegetation to make the massive, arid lakebed suitable for major new uses.
How would wildlife and habitats be affected?
The drying up of Lake Mead would devastate the habitats that currently surround the lake. Riparian zones around reservoir shorelines would disappear, as would productive wetlands.
Many species would lose their homes or see their populations decline:
- Birds – Over 300 bird species rely on Lake Mead for food and nesting. The lake’s wetlands support migrating waterfowl and shorebirds like herons, egrets and plovers.
- Fish – Sport fish like largemouth bass, striped bass and sunfish would disappear from the lake. Native endangered fish like the razorback sucker rely on lake habitats.
- Mammals – Bobcats, bighorn sheep, ringtail cats and other species would decline as the lake vanishes.
- Reptiles – The lake supports desert tortoise and other reptiles that would lose key water sources.
Invasive species like tamarisk and cheatgrass would likely take over areas formerly underwater. This would further degrade habitat value for native plants and animals. Some wildlife would adapt by shifting to the smaller reservoirs still pooling downstream along the Colorado River. But overall biodiversity would suffer.
How would the drying of Lake Mead impact the economy?
The drying up of Lake Mead would have major economic ripple effects across Nevada, Arizona, and beyond. Key impacts would include:
- Reduced regional water security – Lack of water from Lake Mead would require costly investments in desalination, water recycling, pipeline infrastructure, and water imports for cities and farms.
- Loss of Hoover Dam hydropower – Eliminating green power generation from Hoover Dam would increase energy costs and reliance on fossil fuels.
- Decline in tourism revenue – Las Vegas and other regional destinations would see visitor numbers decrease with loss of lake recreation.
- Increased costs for water – Households and businesses would pay more as utilities pass on costs for replacement water supplies.
- Impacts to agriculture – Farmers in places like California’s Imperial Valley would struggle with less Colorado River water.
- Ecosystem/fishery degradation – The economies built around Lake Mead’s habitats and abundant fisheries would collapse.
One 2014 study estimated Southern Nevada would see economic losses between $7.6 billion and $15.7 billion from expected Lake Mead water declines by 2060. The full drying up of the reservoir would lead to even larger regional economic effects over time.
Could desalination help provide replacement water?
As water levels in Lake Mead continue to drop, desalination of ocean water is one option being explored to provide alternative water supplies. Several desalination facilities are already proposed for California, and Nevada has considered coastal desalination options in Mexico.
Desalination uses reverse osmosis and other processes to remove salts from seawater. This technology can reliably produce fresh, potable water. However, there are some downsides:
- High energy use – Desalination is very energy intensive, often relying on fossil fuels.
- Expensive infrastructure – Large capital investments are needed for desal plants and conveyance pipelines.
- Environmental impacts – Desalination can harm marine life from inlet pipes and high-salinity brine discharge.
Even with these challenges, some level of desalination will likely be part of the solution if Lake Mead continues declining. But because of the costs and scale limitations, desalination cannot single-handedly replace all the water lost from a dried-up Lake Mead. Conservation and reuse will also be crucial strategies.
What water conservation steps can households take?
With the threat of Lake Mead drying up, residents can take steps around their homes to use water more efficiently:
- Replace inefficient plumbing fixtures – Install low-flow toilets, faucets, and showerheads to reduce indoor water use.
- Repair leaks – Fix any leaky faucets, pipes, or valves, which waste large volumes over time.
- Adjust sprinklers – Aim sprinklers to avoid overspray and runoff. Upgrade to water-efficient models.
- Landscape with drought-tolerant plants – Replace turf grass with xeriscaping more suitable for the region’s arid climate.
- Use recycled and grey water – Install systems to reuse household wastewater for irrigation and other purposes.
- Take shorter showers – Reduce shower times to conserve hot water.
Adopting these and other conservation tactics in homes, hotels, businesses and facilities throughout the Southwest is crucial for making every drop of water count.
What policy changes could help manage Lake Mead’s decline?
Stopping the decline of Lake Mead will require policy changes to curb water demands and stabilize the overallocated Colorado River:
- Renegotiate Colorado River Compact allocations – The states should negotiate reduced water allotments that match actual river flows in a collaborative process.
- Limit urban sprawl – Groundwater pumping and new development should be controlled through zoning and permitting reforms.
- Restrict unsustainable agriculture – Policymakers may need to restrict activities like cattle grazing and alfalfa farming that use huge water volumes.
- Reform water rights laws – Doctrines of “use it or lose it” encourage waste under the current laws and need updating.
- Establish water markets – Allowing voluntary water trades and sales could shift limited supplies to higher value uses.
- Boost water prices – Appropriately pricing water to reflect its full value would encourage efficient use and curb waste.
Many outdated policies contribute to the current water crisis in the Southwest. Evolving laws and institutions will be necessary to prevent the worst-case scenarios for Lake Mead.
Conclusion
The potential drying up of Lake Mead would bring severe repercussions for over 25 million people across seven U.S. states and Mexico. Las Vegas and distant agricultural regions rely heavily on the reservoir’s water. Allowing Lake Mead to cross the threshold into “dead pool” territory would trigger an exorbitant economic and ecological crisis.
Preventing dead pool conditions must become a top policy priority. Conservation, reuse, desalination projects, updated laws, and sustainable limits on uses can help stabilize Lake Mead. But time is running short. The entire region’s leaders must act decisively to avoid catastrophic and costly impacts if Lake Mead continues drying up in the coming years. The economic and social well-being of millions of people depend on the future of Lake Mead.