Lake Mead critical elevation guide

Lake Mead at 1,035 Feet: Hoover Dam Power Threshold

At elevation 1,035 feet above mean sea level, Hoover Dam reaches a major turbine-operating transition. It is not minimum power pool, and it does not mean that all hydropower generation stops.

Lake Projections reference guide

In brief

What this elevation does—and does not—mean

  • Reclamation's July 2026 Final EIS uses the area around elevation 1,035 feet as a major change in Hoover Dam's usable turbine fleet.
  • That analysis says five wide-head units would be usable while 12 older turbines would face excessive cavitation and would not be used.
  • This is a Hoover Dam equipment and power-capacity threshold. It is distinct from the shortage-tier elevation boundaries in the 2007 Interim Guidelines.
Schematic Lake Mead elevation scale placing the 1,035-foot power transition at 1,035 ft among Hoover Dam's three low-elevation thresholds
1,035 ft in context with the other Hoover Dam thresholds. Lake Projections schematic based on elevations in Reclamation's July 2026 Final EIS, Technical Appendix 15.

What changes at 1,035 feet

Hoover Dam has 17 commercial generators. Reclamation's July 2026 Final EIS describes the area around Lake Mead elevation 1,035 feet as the point where only five wide-head turbines would be usable. In that analysis, the 12 older turbines are expected to sustain excessive cavitation damage and would not be used.

The Final EIS reports an estimated generating-capacity reduction from 1,274 megawatts to 382 megawatts at this transition. Actual output also depends on water release, hydraulic head, equipment availability, and operating needs.

Why power does not stop here

The wide-head turbines were designed for lower reservoir elevations. Official documents describe them as capable of continuing below 1,035 feet toward the estimated 950-foot minimum power pool. The 1,035-foot line therefore marks a steep change in usable equipment, not zero hydropower.

In May 2026, Reclamation announced funding intended to replace up to three older turbines with wide-head units. Because that work can change the operating fleet, equipment counts should always be read with the date of the cited source.

How to use the threshold in a forecast

A deterministic forecast line crossing 1,035 feet shows that one scenario reaches the power transition; it does not state the probability of that outcome. Compare the dated forecast with the latest observation and use an ensemble product when making probability statements.

Do not substitute this elevation for shortage rules. Water-delivery determinations use separate operating criteria and official annual decisions.

Primary references

Sources

Forecasts are planning information, not guaranteed outcomes. Use official Reclamation notices for current operating decisions.