“Pretty much anybody needs to be prepared for the possibility that they may have to evacuate quickly,” said Sacramento meteorologist Brooke Bingaman.
Though most of the valley avoided further flooding Saturday night, the worst may be yet to come Monday and Tuesday, Bingaman said.
Those living anywhere near a slough, a levee, a creek or a canal need to be ready to flee flood waters at a moment’s notice, she said.
Case in point: Maxwell, a rice-farming town of 1,100 people an hour north of Sacramento. It suddenly flooded early Saturday morning as storm runoff overwhelmed a local creek, filling a neighborhood and small business district with more than a foot of water.
Bingaman said the same scenario in Maxwell could happen in just about any low-lying area.
“We have been hit hard with storm after storm after storm since early January, so our soils are very saturated and it’s getting to the point where there’s no place for the water to go,” she said.
In Maxwell, the floodwaters were receding and only one person was still at a Red Cross shelter in nearby Williams Sunday morning, said Jim Saso, assistant sheriff at the Colusa County Sheriff’s Office. But with the next storm approaching, he urged residents to be ready to get out again.
“If they were affected (by the floodwaters) before, they’ll probably be affected again,” Saso said.
Highways in the area remained a mess Sunday.
State Route 162 between Willows and Oroville was closed due to flooding, according to the California Department of Transportation.
About 5 miles north of the Glenn County town of Willows, traffic on Interstate 5 was reduced to one lane in each direction Sunday because of flooding, Caltrans said
State highway officials also warned motorists heading west toward Clear Lake on Highway 20 to expect delays of up to three hours.
On the other side of the Sacramento Valley at the troubled Lake Oroville dam, engineers said the lake is ready to handle the influx of water from the approaching storms.
Officials said Sunday morning that the the lake levels continued to dip and are where they should be for this time of year to catch flood waters.
The lake was at 852 feet Sunday morning, 48 feet below the dam’s emergency spillway.
On Feb. 7, in the midst of winter storms, DWR engineers discovered a cavernous hole in the lower section of the dam’s main spillway, a 3,000-foot concrete span that acts as the dam’s primary flood-control outlet during the rainy season. Fearing the spillway would become inoperable, dam operators stopped the flows for a time, then gradually reactivated releases.
With runoff from the stormy Sierra Nevada still rushing in, reservoir levels climbed, and on Feb. 11, water overtopped the dam’s emergency spillway for the first time in its 48-year history. Unlike the main spillway, which is lined in concrete, the adjacent emergency spillway dumps water in uncontrolled sheets over a 1,700-foot concrete lip onto a steep, wooded hillside.
The next afternoon, a day and a half after the emergency system activated, the hillside just below the spillway lip was showing serious erosion, raising fears the structure would collapse. The concerns prompted mandatory evacuation orders for Butte, Yuba and Sutter counties covering nearly 200,000 people.
The order was lifted Tuesday, after DWR cranked up releases on the main spillway, despite the damage to its midsection, and managed to lower reservoir levels below the emergency lip.
On Sunday, the flows out the main, damaged spillway had been reduced to nearly half as much as much as they were during the heat of the crisis. Officials said the lower flows were allowing crews to use cranes and dredges to clear the debris that formed in the channel below the spillways. The debris has raised water levels to the point that Oroville’s power plant – the dam’s primary release outlet outside of flood season – can’t operate.
Once the debris is cleared and the power plant is restarted, the facility is capable of draining another 14,000 cfs from the lake.
“We’re shooting to be able to re-operate it a week from Monday if we need to,” said Chris Orrock, a spokesman for the Department of Water Resources, which manages the dam. But he noted “it’s not a guaranteed date.”
Meanwhile, despite of the wet weather, crews continue to haul rock and cement into the eroded areas below the emergency spill in case it should need to be used again.
Ryan Sabalow: 916-321-1264, @ryansabalow
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