Outdated Anderson Reservoir can't drain water fast enough

Following days of continued downpours, Anderson Reservoir's overflow spillway is a raging river at a rate of 22,400 gallons per second.

"When you think about releases, you think the district was releasing water," said Jim Fiedler, the chief operating officer of the Santa Clara Valley Water District.  "Releases of water were not done by the district. It was Mother Nature basically have water come over the spillway."

Ultimately, millions of gallons of water went over and down into the Coyote Creek, eventually inundating several San Jose neighborhoods. Thousands of residents have been chased from their homes and are under either voluntary or mandatory evacuation orders.

“There’s no question that we'll need to do things differently next time," said San Jose Mayor Sam Liccardo. "But understanding what those things are, is going to require us to assess better what happened that led to this."

One of the problems is outdated technology for a reservoir and dam built back in the 1950s. Anderson's only release valve can't drain water fast enough, and then add to that the recent round of storms and city leaders say that cause a 100-year-flood level event. There are plans to fix this.

"We're working on a project right now. We're in the design phase to rehabilitate Anderson Dam,” said Fielder.
Fiedler said the new plan replaces the current release valve with one that has an opening two and a half times larger.

Additionally, a new release valve will be built leading to the spillway. It enables officials to drain Anderson in three-to-five days, before it reaches 100-percent capacity and starts sending water down its spillway.

"To give us greater control of the water that flows in the dam," Fiedler said.

Even with streamlined red tape and local approval, the fix won't be finished until 2024 at best. So until then it falls on politicians and first responders to see potential troubles before they're swamped by them.