2026 Colorado River Hydro Update
An unusually weak winter snowpack was wiped out by a warm March, leading to historically low water levels at the two largest reservoirs on the Colorado River System, and ominous projections for hydro generation at Glen Canyon and Hoover dams.
Nearly 40 million people in seven states and part of Mexico depend on water from the Colorado River System. The dams and their storage reservoirs not only provide reliable and affordable power but also flood control; municipal, agricultural, and industrial water; recreation opportunities; and fish and wildlife habitat.
Colorado River Basin Map — U.S. Geological Survey
Colorado River Basin Map — U.S. Geological Survey
Glen Canyon Dam — Colorado River, Arizona, USA
Glen Canyon Dam — Colorado River, Arizona, USA
- While the combined nameplate capacity of Glen Canyon and Hoover dams is roughly 3,400 MW, the plants are currently generating power at about a third of that due to the low reservoir levels (382 MW at Hoover Dam and 730 MW at Glen Canyon Dam, as of mid-September 2026).
- A 2026 study on Glen Canyon Dam led by Argonne National Laboratory found that, “due to the relatively small impact of the loss of generation compared to the size of the rest of the Western Interconnection, there are no concerning reliability impacts” even in a scenario in which Glen Canyon Dam generates little to no power for extended periods.
- WECC is examining several scenarios in which generation is diminished or lost at the two dams, as well as hydro facilities across the West. The results will be available in the 2026 Western Assessment of Resource Adequacy, to be released in February 2027.
- Losing the two dams’ generation could challenge the integration of variable resources, such as wind and solar, and would lead to higher costs for utilities, especially rural electric cooperatives.
- Hoover and Glen Canyon also provide ancillary services, and the power generated at the facilities is dispatchable and flexible, meaning its output can be ramped up and down to match the power needs of the Desert Southwest.
Lake Powell
Glen Canyon Dam
Lake Mead
Hoover Dam
Lake Powell — Glen Canyon Dam
- Maximum power pool elevation: 3,700 feet
- Minimum power pool elevation: 3,490 feet
- Dead pool: 3,370 feet
- Current level: 3,517 feet (September 9)
- Year-end projection: 3,507.68 feet
- Nameplate capacity: 1,320 MW
- Generating capacity at current pool elevation:
730 MW - Generating capacity at minimum power pool elevation: 630 MW
- Maximum annual net generation: 8,703 GWh (1984)
- 1980–2013: Gross annual generation averaged 4,717 GWh annually
- Between 2000–2023, generation declined by an average of 17%
Lake Mead — Hoover Dam
- Maximum power pool elevation: 1,229 feet
- Minimum power pool elevation: 950 feet
- Dead pool: 895 feet
- Current level: 1,039 feet (September 9)
- Year-end projection: 1,037.31 feet
- Nameplate capacity: 2,074 MW
- Generating capacity at current pool elevation: 382 MW
- Generating capacity at minimum power pool elevation: 117 MW
- Maximum annual net generation: 10,348 GWh (1984)
- Minimum annual net generation: 2,648 GWh (1956)
- 1947–2008: Net generation averaged 4,200 GWh annually
Net generation by month at Glen Canyon and Hoover dams dating back to January 2023
Net generation by month at Glen Canyon and Hoover dams dating back to January 2023
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