Is It Finally Time for Glen Canyon Dam to Go?

Four years ago, the Glen Canyon Institute wrote that the “glory years” of Glen Canyon Dam, which generates electricity for about five million people, may be coming to an end. Instead of addressing that problem head on, the Trump administration’s guidelines call on the Lower Basin states of Arizona, Nevada, and California to dramatically reduce their consumption for the next two years by more than one million acre-feet annually.  

Arizona will suffer the largest cut of 31 percent of its supplies from the river, with the Phoenix and Tucson areas being the hardest hit. The Upper Basin states of Colorado, Wyoming, Utah, and New Mexico won’t be forced to cut their usage for now. 

Reclamation also has completed a ten-year environmental impact statement, including possible ranges for operation of the two large reservoirs, Lake Powell and Lake Mead. According to some, the bureau’s plan delays the inevitable bypass of Glen Canyon Dam, an option the government has considered in the past to some extent but not chosen. Circle of Blue reports the bureau is currently studying options for retrofitting Glen Canyon Dam to accommodate a lower Lake Powell and will release findings later this year or in early 2027. 

To sustain the Colorado River by “retiring” the dam is not a new idea. Dan Beard, a former Bureau of Reclamation commissioner, told E&E News in 2023 that Lake Powell is not essential to the operation of the river system, while the lower reservoir, Lake Mead, is.

As water levels drop at Lake Powell, Glen Canyon Dam has been making less hydropower. If the reservoir were full, it could generate 1,320 MW, but now with the reservoir at record low levels the bureau says it has generated only 570 MW. Organizations that have bought power generated by the dam have already looked for alternative sources. This is not a new development. Jerry Wilhite of the Western Area Power Administration told the Colorado Sun two years ago that 14 of the lowest energy production years at the dam had occurred since 2000, the year that the current megadrought made worse by climate change started.

Keeping Glen Canyon Dam as it is while generating less power has consequences. Gary Wockner with the organization Save the Colorado, told H2O Radio that some water stored in Lake Powell is lost to evaporation and to seepage into the sandstone. The Glen Canyon Institute estimated that the reservoir loses about 860,000 acre-feet a year to evaporation and seepage, more than the amount used by the City of Los Angeles each year. The institute adds that water sent from Upper Basin states to fill Lake Powell could have been used by farmers upstream but will end up in the atmosphere or in the ground. 

The bureau’s guidelines issued last week said they are not to be construed as a precedent for future operations. However, Wockner said that the plan, instead of moving toward Glen Canyon Dam’s modification or bypass, locks in this method of dealing with the crisis, i.e., reducing allocations to water users mostly farmers, which is more likely as climate science shows the region is getting drier.

Tires that come on new cars typically give drivers better mileage because they have low “rolling resistance.” Rolling resistance is a measure of how much a tire flattens and rebounds as it travels along the ground. The more it squishes, the more energy it takes—whether from gas or from a battery—to keep the wheels turning. When consumers replace tires, they are often less efficient, resulting in lower mileage and range. By 2033, California’s Replacement Tire Efficiency Program (RTEP) will require tires to match the efficiency of the average new car tire. 

The California Energy Commission, which unanimously approved the standard, says it will save nearly $1 billion in gasoline and electricity costs per year and reduce carbon dioxide (CO2) emissions by two million metric tons annually—the equivalent of taking approximately 400,000 gasoline cars off California roads. 

In a press release, the agency said the incremental cost for consumers is very low—only $1.50 per tire during Phase 1 (2029-2033) and up to $6.50 per tire during Phase 2 (2033 and beyond) but would be offset by fuel savings. By their calculation, a typical driver of a gas car with more efficient tires will save $179 of gas over the life of a set of tires—a figure calculated before the spike in gas prices caused by the Iran war.

There was some resistance from tire manufacturers and industry groups who published a letter opposing the standards, saying they would increase costs during an affordability crisis and would exceed projected savings. However, the tire manufacturers Bridgestone and Michelin, who were involved in the five-year rulemaking process, embraced the new program. 

Naturally, they clam up, according to researchers from Aarhus University. The team found that when blue mussels (Mytilus edulis) detect parasitic flatworms nearby, they slow their filtration of seawater. And when things got really scary with more than one parasite around, they closed their shells completely.

Blue mussels feed by filtering microscopic algae from seawater and a single mussel can filter up to 100 liters a day, affecting water clarity and nutrient cycling. Their beds also provide habitats for small animals, fish, and plants.  The mussels have a well-developed sensory system capable of detecting chemicals in water that could mean a threat is nearby. But that leaves the bivalves with a conundrum—stop eating or risk ingesting something deadly. 

The research suggests that if a whole bed shuts down, it could affect the amount of organic matter in the water and the flow of energy through the ecosystem. The team made their observations in the lab by exposing blue mussels to different species of parasitic flatworms. When the mussels detected the presence of the parasite, they reduced filtration by 34 percent. When the team added a second worm, activity fell by 51 percent compared with the control group.

The team says that because ocean parasites tend to prefer warmer water—and mussels get “scared” when they’re around—their reaction could become more common with climate change if flatworms muscle in.

The study was published in the Journal of Helminthology.