The forecast does not look good for the California flooding crisis
- Author: Rogelio Becker Feb 15, 2017,
Feb 15, 2017, 0:13
As of noon, dam operators were releasing 100,000 cubic-feet per second of water down the broken regular spillway, which started coming apart on February 7.
The good news, Mathews noted, is that the forecast amount of rain over the next few days in northern California is less than half the 12 to 20 inches that drenched the region last weekend, which caused the original damage to the spillway and forced almost 200,000 people to flee their homes.
"We hope everyone remains safe as the evacuations continue and we will be working alongside with FEMA and appropriate government entities to make sure that we are doing everything we can to attend to this matter", Spicer said. Crews operating heavy equipment loaded rocks and boulders into dump trucks, which carried them over the dam and dumped them on damaged portions.
Water authorities had been relieving pressure on the dam through the concrete-lined primary spillway last week, but lake levels rose as storm water surged in and engineers moderated use of the damaged primary spillway.
The operators at America's tallest dam found themselves in a precarious position Monday, with both of the spillways used to release water compromised and the reservoir still filled nearly to capacity after a winter of record rain and snow.
Residents below the dam were ordered to evacuate their homes Sunday when an emergency spillway that acts as an automatic overflow channel appeared on the brink of collapse from severe erosion.
Dozens of schools in evacuation areas throughout Yuba, Sutter and Butte counties are closed.
The Federal Energy Regulatory Commission, which regulates dams that produce hydropower, also wants an independent forensic analysis of the spillway's failure.
At 770 feet (230 meters) high, the structure, built between 1962 and 1968, is the tallest USA dam, exceeding the Hoover Dam by more than 40 feet (12 meters).
One meteorologist's estimate on February 13 showed at least 400 billion gallons of water flowing into Lake Oroville during the next seven days. Water poured down the hillside toward Oroville and towns further downstream.
In total, it's possible that some parts of California, potentially including the area that drains into Lake Oroville, could see up to 9 inches or more of rain in the next seven days.
California Department of Water Resources engineer Eric Holland, in the Division of Safety of Dams, said restrictions on capacity affected 64 reservoirs out of the 1,250 dams overseen by the agency. In those guidelines, he said Monday, "they talk about how you don't put a lot of funding and concrete, etc. into emergency spillways because presumably they will rarely if ever be used". "This was a new, never-happened-before event".