MORGAN HILL (KPIX 5) — The Santa Clara Valley Water District wants to move quickly to drain the Anderson Reservoir and seismically retrofit the dam, but it also wants to move carefully to minimize impacts once the water is let go.
Anderson Dam was built in the 1950s and is made from earthen materials like soil, gravel and rocks. But for the last few years, its water levels have been purposely kept below half full to minimize risks of a dam failure if a major earthquake were to hit the area.
Now, the federal agency that regulates dam safety says even that much water poses too great of a risk and has ordered the Valley Water District to drain it.
“We’ve known about the condition of the dam for some time and our staff has been working with regulators as it relates to making retrofit improvements to the dam. We want to move quickly on this project to make sure we bring safety to our community,” said Nina Hawk of the Santa Clara Valley Water District.
But the district is also concerned about the loss of water supply, potential flooding, habitat loss and fish kills on Coyote Creek, which starts at the base of the dam and could run dry if the reservoir drains out.
“I think it’s going to be disastrous for the area,” said Morgan Hill neighbor Peggy Lloyd Talbot, who’s been coming to Coyote Creek with her horses and dogs since she was a teenager.
She worries about the loss of a resource and habitat for all animals if the reservoir and the creek dry up.
“You can’t find water nearby, when that’s gone,” Talbot said.
Water officials say the loss of Anderson’s water for household and business use will be felt, but not critically. Groundwater levels are full and water is still being imported into the valley from the Northern Sierra and the Delta.
“It’s not a disaster because we’ve got five other sources of water,” said Pat Ferraro, a former Water District Director and an Environmental Studies lecturer at San Jose State University.
“The disaster is if the dam fails with water in it, that’s the only possible disaster. Having the feds get involved has just accelerated the process of getting the dam repaired,” he said.
The water district says repairing the dam will take between two and five years, and should be a process that balances earthquake safety, water supply and environmental impacts.