news that the lake Powell, a reservoir on the border of Arizona and Utah, is slowly but surely drying up and spreading far and wide. Behind the 1,320 MW Glen Canyon Dam and Power Station, Lake Powell is instrumental in providing electricity to approximately 3 million customers in Arizona, Colorado, New Mexico, Utah and Wyoming.
But this year, the reservoir has depleted historically due to ongoing drought conditions in the region, which have been at least partly attributed to climate change. The dam could shut down power generation if the situation continues to worsen, and the issue is not alone in the American Southwest.
The Colorado River, an important source for many dams and power plants in the region, has been devastated by drought for the past 22 years – some research suggests the region is subject to the worst drought in 1,200 years. In addition, according to the US Drought Monitor, as of March 29, 88.75 percent of the western US is experiencing moderate drought or worse. Other dams in this dry part of the country are seeing similar effects, according to staff members from the United States Bureau of Reclamation – although officials also noted that each case is different.
According to Becky Bryant, Upper Colorado Basin Public Affairs Officer for USBR, there are two main factors affecting hydro production. The first is the amount of water that passes through the generator of the dam. The second is the depth of the body of water that feeds the dams. In deeper bodies of water there is a greater force behind the generator’s turbines to spin and rotate the water.
Lake Powell and Glen Canyon Dam make an extreme case in the US. The dam’s minimum power pool (MPP) – the point at which hydropower can no longer be produced in the dam – is approximately 1,064 metres. It is currently sitting at 1,075 metres. Estimates suggest there is a 23 to 27 percent chance it will hit the MPP every year from 2023 to 2026, according to Bryant. Other parts of the Colorado River basin, which is home to a few other dams, are also being affected by drought. The 22-year drought has reduced the amount of energy produced in the region by 13.1 percent, compared to the average annual energy production in the preceding 12 years (from 1988 to 1999). “It is difficult to predict the actual impacts after 2023, but this trend is projected to continue,” Bryant said.
california is dreaming
California has also dried up in news that did not shock anyone in the state. However, according to Steven Melavik, head of power operations for USBR’s Central Valley Project, the nature of California—which is home to many hydro operations—is somewhat different from Arizona. Carrie Foxx, a team lead with USBR, said that if the Shasta powerplant’s reservoir was completely full, it would be a 710-megawatt plant. Currently, the water in its reservoir is so low that it is expected to produce about 380 MW less by the end of the fall.
However, due to wet storms coming from the Pacific Ocean, California’s reservoirs can quickly fill up. “Reservoirs can rebound in one heartbeat. It’s a different kind of dynamic,” Melwick told Ars.
But Fox notes that reservoirs really only winter and fall to refill with precipitation. “If there’s no rain or snow in the winter, that’s all. We have a season … This year, it didn’t happen,” Fox said.
