In Peril at Oroville Dam, a Parable on Infrastructure

California officials have ordered the evacuation of nearly 200,000 people downstream from the Oroville Dam because overflowing waters could erode the dam’s two spillways and cause devastating flooding.

Yet when public interest groups warned of such a threat in 2005, state and federal officials rejected their call to line one spillway with concrete, saying it was unnecessary, The San Jose Mercury News reported on Sunday.

Water flowing Saturday over the emergency spillway, bottom left, of the Oroville Dam in California (Randy Pench / Sacramento Bee via Associated Press)

The danger to Oroville, north of Sacramento, is the latest wake-up call that American public works are crumbling after decades of neglect, and the federal and state governments need to spend hundreds of billions on repairs.

The crisis started after big storms and mountain runoff filled Lake Oroville beyond its capacity and a large hole opened up in the dam’s main spillway that releases water into the Feather River. That forced officials, for the first time in the 49-year history of the dam, to temporarily use an emergency spillway, an unlined hillside prone to erosion. Eroded material pouring downstream can damage levees along the river.

Lake Oroville is the second-largest reservoir in California and is a crucial part of a massive system that moves water from the Sierra Nevada range to farms and homes farther south. Its dam — which is considered sound — is the tallest in the United States and widely thought to be an engineering marvel.

The emergency spillway, however, has been a concern. When the Friends of the River, the Sierra Club and the South Yuba River Citizens League asked the federal government in 2005 to make California line it, the state and water utilities said doing that was unnecessary and the Federal Energy Regulatory Commission agreed.

Oroville is hardly an isolated case. The American Society of Civil Engineers gives the country’s dams an average grade of “D” and estimates that at least $21 billion is needed to fix aging, high-hazard dams. The average age of the country’s 84,000 dams is 52 years, and 70 percent of them will be more than a half-century old by 2020. Groups like American Rivers argue that many of these dams should be removed in the interest of public safety and to return waterways to their natural state.

President Trump has promised $1 trillion in infrastructure spending, but he has provided few details and Republican leaders in Congress have balked at the cost. Mr. Trump’s advisers have suggested that the goal could be accomplished through tax credits for investors. Such an approach might provide profits to developers of toll roads or bridges with cash flows, but it isn’t a strategy to keep public works like the Oroville Dam safe.