Update 8:43 p.m. (AP) - Conservation groups are urging extensive and swift repairs at the nation's tallest dam, where an eroding spillway triggered an evacuation order for nearly 200,000 people in February.
The groups warn in a filing Wednesday with the Federal Energy Regulatory Commission that state should construct a concrete backup spillway to protect downstream communities below Northern California's Oroville Dam.
They also want more communication and transparency from the government on the work.
On Feb. 7, a massive crack opened in the main spillway at the dam. For days, managers assured the public there was no imminent danger as they slowed releases of water to assess the damage.
Then, a backup spillway started falling apart, triggering the evacuation.
The groups include the Friends of the River and Sierra Club California.
An Associated Press review found officials made a series of questionable decisions and missteps before and during the crisis.
Original post: (AP) - An Associated Press review has uncovered a series of questionable decisions and missteps before and during a crisis at America's tallest dam.
In February, a massive crack opened in the main spillway at the Oroville Dam in Northern California.
For days, managers assured the public there was no imminent danger as they slowed releases of water to assess the damage.
Then, a backup spillway started falling apart, triggering an evacuation order for nearly 200,000 people.
The AP has found the dam received an uncommon exemption from federal rules requiring it to release huge amounts of water.
And government overseers overestimated the durability of the two spillways.
State water officials say the crisis was managed as effectively as possible.
Now Democrats in the U.S. House want the auditing arm of Congress to review dam safety standards following the crisis at the nation's tallest dam.
The group that includes six House members from California tells the Government Accountability Office that a changing climate raises risks for aging dams around the U.S.
They say there is a "real crisis for dam safety."
Managers at the dam made a critical mistake by allowing the lake behind it reach its highest level ever.
That's according to Bill Connolly, a Butte County supervisor in California whose district includes Oroville Dam.
Connolly says that backup spillway was never intended to be used for flood control so "they never should have let the lake overflow."
He calls the dam poorly run.