How Glen Canyon Dam might be fixed to keep power flowing

Construct a new intake structure to allow Colorado River water at low levels to flow from the eight penstocks on the dam’s face into the turbines inside the dam. The intake would be built at 3,285 feet elevation, 205 feet below the lowest level at which the dam now can generate electricity.

Build four new, mid-level intakes at 3,445 feet elevation to connect the penstocks to the turbines.

Extend the dam’s river outlet works — steel tubes lying at the base of the dam, well below 3,490 feet, that will have to be used to move water through the area when Powell falls that low. These outlet tubes would be equipped with power plants, to increase power production at lower lake levels.

Refit two of the dam’s turbines so they can take water coming from the outlet works, which lie well below the turbines’ water level. This allows more water at lower elevations to enter the turbines than is currently possible.

Drill a tunnel through the dam’s left, sandstone abutment, underneath the main dam structure. The tunnel would connect to an underground power plant that would allow electricity to be generated below 3,490 feet.

Drill a tunnel through the dam’s right sandstone abutment, also underneath the main dam structure. This would allow water to flow through a new power plant built at the level of the riverbed, well below 3,490 feet. This alternative would require a new bridge from the base of the existing power plant at the dam to the new power plant, downstream of the dam.

Adjust system-wide river operations, to get more water into Powell to maximize power generation. This could involve a continuation if not increases in past years’ releases from upstream Colorado River Basin reservoirs such as Flaming Gorge at the Utah-Wyoming border to prop up Powell’s water levels.

Use computer models to determine how low the lake would have to fall to allow whirlpool-like vortexes to form that would entrain air first in the water, then in the dam’s turbines, leading to cavitation. That’s a structurally unstable phenomenon that can cause turbines to wobble and possibly break. The vortexes can also suck in equipment and even fish from the water that can damage the turbines. Once that analysis is done, the bureau could install large structures to break up vortexes in the water and reduce cavitation risk.

Build solar and wind power generating facilities on land near the dam, to replace some of the hydropower lost when the lake falls too low to operate the turbines.