Reservoirs feeding Lake Oroville are filled to brim as more rain rolls in

Article from Sacramento Bee.

February 20, 2017 8:26 AM
By Jane Braxton Little

Lake Almanor is full. So is Antelope Lake.

In fact, all of the nine reservoirs in the Feather River watershed that feed directly into Lake Oroville are brimming with water from recent storms.

With more rain falling and another even heavier storm predicted for Monday and Tuesday, Plumas County officials are anxiously watching both the sky and the reservoirs above their communities.

“I’m watching, and I’m worried,” said Plumas County Supervisor Kevin Goss.

The last set of storms flooded his Indian Valley district, pinning Goss in his home 20 miles from Greenville, isolating Greenville and Taylorsville from one another, and blocking travel out of the area in all directions. Flooding damaged sewer systems and roads all over Plumas County, an expanse of rugged terrain that sits to the northeast of Oroville and includes part of Lassen Volcanic National Park.

Poised alongside reservoirs managed for hydropower and water users as far away as southern California, community leaders throughout the rural region wonder how the combination of additional rain and full-to-the-brim reservoirs will affect their districts as well as Oroville, where managers are trying to unload as much water as possible down the dam’s damaged main spillway to make room for more coming in.

High in the headwaters above the ranches of Indian Valley, Antelope Lake holds around 27,000 acre feet of water. Operated by the California Department of Water Resources, Antelope is part of the State Water Project. It flows into a series of streams before emptying into Lake Oroville, which provides drinking water to more than 23 million people.

Last week, when ranchers and residents were flooded out of their homes in the valleys below, Antelope operators released 2,362 acre feet of water over six days. The largest single release – 714 acre feet – came on Feb. 10, when flooding across Indian Valley swept a Taylorsville resident off a bridge and into the creek near Crescent Mills. He survived.

Goss has not been contacted by DWR officials, he said, and has no information about how the Antelope releases affected his district.

DWR officials were preoccupied with the situation at Oroville and unavailable for comment on how they manage Antelope Lake. “I don’t even know where that reservoir is,” said DWR spokesman Chris Orrock, preoccupied with the situation at Oroville, where nearly 200,000 people were briefly ordered to evacuate last week amid fears that the dam’s emergency spillway would fail.

Antelope is one of nine reservoirs that provide water to Lake Oroville. Three are managed by DWR; one is operated by the South Feather Water and Power Agency. The other five are owned and operated by Pacific Gas & Electric Co., producing electricity as part of the Feather River Stairway of Power.

The largest of these is Lake Almanor near Chester. It stores 1,142,000 acre feet, around one-third of the storage capacity of Lake Oroville.

During the recent storms, PG&E operators have worked to keep the popular recreation lake below the 4,494-foot elevation maximum, releasing water through a small outlet at the base of the dam as well as a tunnel to Butt Valley Reservoir, 10 miles south of Almanor.

Despite their efforts, water is flowing in as fast as it is flowing out, said Plumas County Supervisor Sherrie Thrall, who represents the Chester/Lake Almanor district. While most reservoirs have the possibility of spilling water during an emergency, spilling water out of Lake Almanor is not an option, she said.

Most of Chester is below the 4,500-foot spillway. If reservoir managers were forced to release water over the spillway near Canyondam, large portions of Chester would be inundated.

“That’s why PG&E is working so hard to maintain a lower lake level,” said Thrall.

PG&E has never used the spillway, said Paul Moreno, a company spokesman.

Thrall is in regular contact with PG&E officials, but she and other Plumas County officials worry that managing the upper watershed reservoirs is a low priority for DWR.

“It’s not in the agency’s mind that Antelope, Lake Davis and Frenchman are even connected to Oroville,” said Robert A. Meacher, Portola city manager and former Plumas County supervisor representing Indian Valley. “We need better coordination in the operation of the entire Feather River system.”

Michael Jackson, a Quincy-based attorney for the California Sportfishing Protection Alliance, said DWR management of its upper watershed reservoirs has always suffered from “benign neglect.” Recently it’s been compounded by “drought mentality,” he said.

When the rains began this month, Antelope levels were too high to allow controlled releases, he said. “They were so concerned with the last five years of drought they weren’t paying attention. And Indian Valley is paying the price,” said Jackson.

PG&E coordinates its reservoir management with DWR and is in daily contact with state officials, said Moreno. Most of the utility’s dams on the Feather River direct water into powerhouses, which return it to the river after spinning turbines that generate electricity.

Moreno estimated the water released from Almanor, Bucks Lake and its other reservoirs at 2000 cubic feet per second. At about 2 percent of what DWR managers have been releasing from Lake Oroville, “it’s the proverbial drop in a bucket,” Moreno said.

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