California crews rush to fix dam before new storms hit

Oroville: Stormwaters receded on Monday behind the nation`s tallest dam, in Northern California, as engineers raced to drain the rain-swollen reservoir and shore up a crumbling overflow channel before new storms sweep the region later this week.

Authorities said they had averted the immediate danger of a catastrophic failure - one capable of unleashing a wall of water three stories tall on towns below.

But evacuation orders for some 188,000 residents remained in effect indefinitely, Butte County Sheriff Kory Honea said at a midday news conference. The risk to those living in the Feather River valley below the Lake Oroville Dam, 65 miles (105 km) north of Sacramento, was still being reviewed, he said.

"We need to have time to make sure that before we allow people back into those areas it is safe to do so," Honea said.

Residents below the dam were abruptly ordered from their homes on Sunday when an emergency spillway that acts as an automatic overflow channel appeared on the brink of collapse from severe erosion during what is on track to be Northern California`s wettest winter on record after years of drought.

Environmental groups had warned for more than a decade that the dam`s spillway was not safe.

“Infrastructure is profoundly important, and in our complex society, whether it`s electricity or gas or water or roads or bridges, there’s a lot to be done,” California Governor Jerry Brown told reporters during a news conference on Monday evening.

Brown said he was pleased by U.S. President Donald Trump’s promise to pursue a $1 trillion infrastructure program, adding, “I’ll strive to make sure California gets 12 percent” referring to the state’s share of the U.S. population.

Local residents were stunned by the ferocity of the waters, like Alfred Ybarra who had gone down to the Feather River with his children on Sunday to take photographs.

"Within minutes the water was up to the tires on my car," Ybarra said. "I told my kids, `You have to pray. It`s the only thing that you can do."

Asked whether he thought officials had overreacted, Ybarra responded, "Absolutely not."

The main spillway, a separate channel, is also damaged because part of its concrete lining fell apart last week. Both spillways are to the side of the dam itself, which has not been compromised, engineers said.

The situation grew less dire later on Sunday as water levels dropped, leaving the weakened unpaved emergency spillway largely intact. By Monday, the level of the lake fell enough so that water was no longer pouring over the hill.

Erosion caused by the hole in the side of the main spillway appeared to have abated by Monday, and it was back to more or less normal operations, officials said.

The aim is to lower the reservoir`s overall water level by 50 feet - and prevent further spillover down the emergency hillside channel - before more rain arrives in the coming days and snow-melt runoff begins in the spring, acting state water resources director Bill Croyle told reporters on Monday. He said he hoped to achieve that goal within two weeks.

Another storm was forecast to arrive as early as Wednesday or Thursday, though officials said they expected much of that precipitation to fall as snow rather than rain.