Lake Mead Elevation Currently 1048 Feet Above Sea Level' - At 1035' Its Generating Capacity Falls By 70%

[hatrack]

Some day in the next 12 months—maybe in late August, maybe not until next spring— Lake Mead will drop below the critical threshold of 1,035 feet above sea level. That is the water-level elevation at which hydropower generating capacity at Hoover Dam, the largest in the Colorado River basin, will be cut by 70 percent. The drastic and immediate reduction in a cheap source of power that is responsive to hourly changes in electricity demand will have consequences for the region’s power customers and the broader electric grid alike.

Water managers have known for at least a year and a half that elevation 1,035 feet will be a problem for Hoover’s hydropower. Twelve of the dam’s 17 turbines are not designed to operate in low-water conditions that would be present when Mead is below that level. After record-low winter runoff into already-depleted reservoirs, water managers now know that the day of reckoning is coming soon.

“We’re going to go to 1,035,” Tom Buschatzke, director of the Arizona Department of Water Resources, said at a meeting in mid-May. “There’s no question that’s going to happen.”

The Colorado River’s big reservoirs, Lakes Mead and Powell, are filled with trip wires—water-level elevations that, once breached, trigger a negative outcome. Both reservoirs are low enough that those trip wires for hydropower generation are in sight. With so little water in the system, water managers are in a triage situation, trying to minimize damage but acknowledging there will be unfortunate tradeoffs.

EDIT

https://insideclimatenews.org/news/12062026/hoover-dam-approaches-a-hydropower-cliff/

https://lakemead.water-data.com/

[Srkdqltr]

1. Cant they fix the dam? Or something?

[hunter]

3. We can't change physical reality.

𝑃=𝜌𝑄𝑔Δℎ

Power output (P) is proportional to the difference between the inlet elevation and the outlet elevation ( Δℎ )

The turbines at Hoover Dam are optimized for a certain Δℎ. Conceivably turbines could be installed or modified to operate at a lower elevation of water behind the dam but the amount of electricity produced would not offset the cost of this modification. It's much less trouble to build natural gas fueled power plants.

In any case, Hoover dam hasn't been a major source of power in recent years and the utilities have already accounted for this. For comparison, in recent times Hoover Dam's total electrical output is about one-tenth that of Arizona's Palo Verde nuclear power station.

[Srkdqltr]

5. Thank you

[hatrack]

4. The generating capacity of all dams falls as water levels fall . . .

Last edited Sun Jun 14, 2026, 12:39 PM - Edit history (1)

At Glen Canyon, they've already had to substantially replace/repair most of the turbine blades in a multi-year process.

This is kind of an oversimplification, but the lower the elevation of water above the penstocks, the lower the water pressure, and as pressure drops, cavitation risk increases.

Formation of air bubbles on turbine blades (or on spillway walls, as the same dam experienced during emergency high-water conditions in 1983) produces micro-explosions capable of eroding metal, concrete and rock.

Main point - if the water gets low enough - i.e. if there isn't enough water above the penstocks to generate power without cavitation risk, you have to limit and/or shut down generation even if there's still enough water to flow through the penstocks.

[NoMoreRepugs]

2. But but but - our AI data centers need it or the future will collapse.