California Faces Another Dam Failure Threat
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On Saturday, the Los Angeles Times front-paged an article with the headline “Concerns are raised over dam’s flood risk.” The structure in question is located in southern suburban California, and the dam’s failure could endanger numerous communities, including Anaheim and Disneyland.

Should Mickey Mouse grab Minnie and run, as California now experiences a rare May rainy spell?

I shouldn’t joke. Dam failures are serious situations, like the near-disaster at Oroville in February 2017 when 188,000 local residents were forced to flee for their lives at the orders of the government. Luckily, the rains slacked off and the dam held.

No thanks to Sacramento. According to a study from the American Society of Civil Engineers ranking the states in 2017 for infrastructure spending, California ranked dead last.

Apparently newish California Governor Gavin Newsom has different spending priorities apart from public safety — like expanding taxpayer-funded healthcare for illegal aliens from kids (now costing $360 million yearly) to young adult aliens, estimated at additional $260 million.

Newsom does want to prepare for climate change, so perhaps he can be convinced that dam repair falls in that category.

Below, the Prado Dam seems a rustic affair, due for a tune-up. (Photo snapped from an overhead video of the curious place.)

The LA Times article was reprinted in the Watertown Daily Times, linked here:

Engineers up failure risk for dam protecting Disneyland, dozens of Southern California cities, Los Angeles Times, May 18, 2019

LOS ANGELES — Federal engineers are raising alarms that a “significant flood event” could compromise the spillway of Southern California’s aging Prado Dam and potentially inundate dozens of Orange County communities from Disneyland to Newport Beach.

After conducting an assessment of the 78-year-old structure earlier this month, the U.S. Army Corps of Engineers announced that it was raising the dam’s risk category from “moderate” to “high urgency.”

“Our concern right now is about the concrete slab of the spillway and how well it will perform if water were to spill over the top of the dam,” said Lillian Doherty, the Army Corps’ division chief. “We will determine whether or not it is as reliable as it should be.”

Located beside the 91 Freeway on the border of Riverside and Orange counties, the dam impounds little to no water for much of the year. During periods of heavy rain, however, the structure is intended to collect water and prevent flooding along the Santa Ana River.

Doherty said her agency is working with a national team of experts to develop interim and permanent risk-reduction measures at the dam, as well as public outreach strategies to alert the estimated 1.4 million people who live and work in 29 communities downstream.

The sudden downgrade in the structure’s evaluation comes after major problems have been identified in other California dams.

In February 2017, a concrete spillway at the Oroville Dam disintegrated during heavy rains and triggered the evacuation of more than 180,000 people. The head of the California Water Resources Department, which operates the dam, was removed after an independent probe found the failure was the result of a lax safety culture.

That same year, the Corps of Engineers discovered that the 60-year-old Whittier Narrows Dam, about 40 miles to the west of Prado Dam, was structurally unsafe and posed a potentially catastrophic risk to more than 1 million people in working-class communities along the San Gabriel River floodplain.

In that case, engineers found that intense storms could trigger a premature opening of that dam’s massive spillway, swamping homes, schools, factories and roads from Pico Rivera to Long Beach. Engineers also found that the earthen structure could fail if water were to flow over its crest.

The Corps estimates it will cost roughly $600 million in federal funds to upgrade the Whittier Narrows facility, which has been reclassified as the agency’s highest priority nationally because of the risk of “very significant loss of life and economic impacts.”

Now, given concerns that Prado Dam poses a flood threat to much of Orange County, the agency is collaborating with Los Angeles, Orange and Riverside counties, and several dozen municipalities, to develop emergency plans that could be implemented before repairs to the dams are completed.

Col. Aaron Barta said the retrofit operations on the spillways at both dams could begin as early as 2021. (Continues)

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