Rain-Swollen Anderson Reservoir On Brink Of Overflowing

MORGAN HILL (CBS SF) -- The largest reservoir in Santa Clara County was almost completely full and well past its seismically safe levels Friday with more rain in the forecast.

The Anderson Reservoir near Morgan Hill can hold 89,491 acre-feet of water and is now 99 percent full, according to Santa Clara Valley Water District spokesman Jim McCann.

However because of "seismic vulnerabilities," the reservoir has been kept to 45 feet below the dam crest, or 68 percent of capacity, since 2009.

If the rains that are expected to hit the area over the next several days materialize, it is likely that the water level will rise to the point at which it reaches the spillway, sending water cascading down the large concrete and earthen ramp and into nearby Coyote Creek for the first time in about 10 years.

"Yes, it is still a possibility. We're watching it," said McCann. "Depending on the inflows around the surrounding area and watershed."

Just because water hits the spillway, however, does not mean that there is an emergency situation at hand.

"It's doing what it's designed to do," McCann said.

The situation at the Anderson Reservoir should not be equated with what happened at Butte County's Oroville Dam, where the possibility of a spillway collapse led to the evacuation of hundreds of thousands of people Sunday, McCann said.

The spillway at the Anderson Reservoir is not damaged, as was the case with the Oroville Dam.

Still, people downstream of Anderson should pay attention to the water level of Coyote Creek and other nearby streams, which could overflow their banks if the upcoming storms drop more rain than currently expected.

The storms that are hitting the region between Friday and Thursday are forecasted to bring up to 2.5 inches of rain to the area, according to National Weather Service forecaster Bob Benjamin.

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