The Santa Clara Valley Water District is concerned about the Calero Reservoir in the Santa Teresa Hills, south of San Jose. The artificial lake, with a surface area of 110 acres, is a major source of water for the region, but over the years, sand, gravel, alluvium, and clay have been accumulating beneath the downstream dam embankment. This claim, authorities said, could seriously damage the dam in the event of a major earthquake.

The Calero Dam, which created the reservoir, was constructed in 1935. The District believes it is now in need of serious repairs, but that could cost tens of millions of dollars, money that is not readily available in the current budget crisis. A comprehensive report on the situation is scheduled to be released in March.

Earthquake Could Do Serious Damage to Calero Lake Reservoir.