(Updates with California request for federal aid)
By Deborah M. Todd and Sharon Bernstein
OROVILLE, Calif. Feb 13 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 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 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 on Monday sent a letter to U.S. President Donald Trump
requesting he issue an emergency declaration, which would open
up federal assistance for the affected communities.
Brown said he was pleased by 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.
Residents were stunned by the ferocity of the waters.
Alfred Ybarra had gone down to the Feather River with his
children on Sunday to take photographs, and they quickly found
themselves in trouble.
"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. 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.
REPAIRS AND DRAINAGE
On Monday afternoon, crews began dropping large bags filled
with rocks into a gap at the top of the emergency spillway in a
bid to rebuild the eroded hillside.
Meanwhile, water could be seen gushing from the main
concrete spillway as dam operators for the California Department
of Water Resources continued controlled releases through the
paved chute into channels that route the water away from
The dam's hydropower release valves also have been shut down
to prevent damage from sediment and debris carried by heavy
The earth-filled dam is just upstream and east of Oroville,
a town of about 16,000 people. At 770 feet (230 meters) high,
the structure, built between 1962 and 1968, is the tallest U.S.
dam, exceeding the Hoover Dam by more than 40 feet (12 meters).
Butte County and environmental groups have fought against a
re-licensing of the dam for more than a decade, legal documents
Conservation groups Friends of the River and the Sierra Club
argued in 2005 that the dam's emergency spillway should be
better fortified and risked severe erosion when water levels
The Federal Emergency Regulatory Commission, which licenses
the dam, denied this, stating in a 2006 memo that “in the rare
event of a discharge, the emergency spillway would perform as
Butte County, meanwhile, argued that it had been left to
police the dam without help from the state to offset costs.
Kathy Ingvoldsen, 41, and her family were among the evacuees
who went to the nearby city of Chico and found a hotel to spend
the night. Although her community lifted its mandatory
evacuation order Monday, she was concerned about how neighboring
towns will fare in the days ahead.
"It's not today that really worries me so much as when the
rain starts again. They're not talking about the big picture,"
(Additional reporting by Jim Urquhart in Oroville, Gina
Cherelus in New York and Curtis Skinner and Robin Respaut in San
Francisco; Writing by Steve Gorman and Dan Whitcomb; Editing by
Peter Henderson and Mary Milliken)