By Jackie King
Despite the fact that California is nearing drought conditions in many parts of the state, federal officers are ordering the draining of Anderson Lake in Morgan Hill. Local authorities, although they disagree with the chosen approach, agree with the need to mitigate the risk of extreme damage due to the possibility of local flooding.
The 240-foot high dam poses an extreme earthquake risk to nearby residents, as the Anderson Dam is right next to the Calaveras Fault. Because of this, federal officers demanded the complete draining of the dam beginning no later than Oct. 1, according to the Federal Energy Regulatory Commission (FERC).
“It is unacceptable to maintain the reservoir at an elevation higher than necessary when it can be reduced, thereby decreasing the risk to public safety and the large population downstream of Anderson Dam,” according to a letter that was written by the director of the FERC, David Capka, which was sent to the Santa Clara Valley Water District, who owns the reservoir.
Anderson Dam, more commonly known to locals as Anderson Lake, has been a popular boating lake for the locals since it was built in 1950. Located in between San Jose and Morgan Hill and holding up to 90,000 acres of water, this dam accounts for more than half of the district’s capacity of 170,000 acre-feet in all ten of its reservoirs.
An assessment by the Santa Clara Valley Water District proved that if there was an earthquake of a magnitude of 6.6 centered at the fault, or an earthquake with a magnitude of 7.2 with an epicenter as far as a mile away, there would be a high chance the dam would be severely damaged. Because of this, officials have left the lake at a maximum of 74 percent capacity. Since this assessment, California has been in a continuous drought, naturally lowering the capacity. On Mon., Feb. 23, Anderson Reservoir was just 29 percent full. As of Feb. 25, more than 60 percent of California is experiencing abnormally dry conditions during what is supposed to be the state’s rainy season, and no more rain is expected until late March.
CEO of Morgan Hill water district Norma Camacho stated that the reservoir is already operating at levels below the requirements set by the FERC and the state’s Division of Safety of Dams. Camacho also discussed the unfavorable impact that draining the entire reservoir could have on residents and the dam’s infrastructure, let alone the wildlife in the area.
“A top concern is the potential to damage the intake structure, which would give us no way to control water flows out of the reservoir, potentially impacting downstream communities,” Camacho wrote. She and other local authorities declare that their preferred solution would be completing the reservoir’s seismic retrofit project, which they have been working on for several years. Constantly changing safety and design requirements have continuously forced the plan into the works for even longer. Construction will hopefully begin in 2022, aiming to prevent the collapse of the dam, which would cause damage to cities and rural areas anywhere from the San Francisco Bay to the north through Monterey Bay to the south.
(Sources: USA Today, Mercury News, NBC Bay Area, Fox News)