Posted December 27, 2017

More California dams have spillway problems

Three dams in Santa Clara County have spillway problems similar to the Oroville Dam.

The spillways at three dams located near densely populated communities around San Jose have structural problems that are similar to the flaws that led to the failure of the main spillway at Oroville Dam last February, recently completed technical reports show.

The concrete spillways at the Guadalupe Dam and Calero Dam, both built in 1935 in the hills south of San Jose, have extensive cracks, flawed joints, and in the case of Guadalupe, gaps of up to 15 inches deep between the bottom of the spillway and the bedrock underneath.

While the prospect of a wall of water wiping out parts of San Jose is indeed alarming, officials say the spillways would only pose a risk if the South Bay is inundated for months with rain filling the reservoirs to their brims. That’s a rarity, although it happened last year at Anderson, Santa Clara’s largest dam.

The spillway at Anderson Dam, built in 1950 east of Morgan Hill, is in significantly better condition than the ones at Guadalupe and Calero, after a modernization project in 1988. But it still has cracks and concrete defects that need repairs, and potential voids requiring further investigation, the reports found.

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Source: San Jose Mercury News