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Water & Drought
By Dale Kasler
dkasler@sacbee.com
March 23, 2016 – 11:10 AM

  • El Niño precipitation forces water flow as drought eases
  • Flood releases are first in years at Oroville, Shasta
  • After years of drought, Northern California has so much water that the state’s two largest reservoirs are releasing water to maintain flood-control safety.

The water releases from Shasta Lake and Lake Oroville don’t mean the drought is over. But they represent the latest evidence that drought conditions are easing as El Niño has brought meaningful amounts of rain and snow to Northern California for the first time since 2012.

Yet the free-flowing water remains a significant source of controversy throughout Northern California. Suburban Sacramentans wondered last month why water was being deliberately spilled out of Folsom Lake instead of stored for future use. Similar complaints are popping up in the northern end of the Sacramento Valley after several days of substantial flood releases from Shasta.

In the Redding area, motorists crossing bridges over the Sacramento River “can see a year’s supply of water going by in less than a day,” said David Coxey, general manager of the Bella Vista Water District. “I’m getting customer calls.”

Lake Oroville is 83% full, or 111% of average for this time of year. A year ago it was roughly half full.

Shasta, the state’s largest reservoir, has been releasing significant amounts of water for several days, the first flood-control releases in five years. Lake Oroville, the No. 2 reservoir in California, is scheduled to begin flood-control releases Thursday for the first time since 2012.

Operators of the state’s reservoirs said they have only limited wiggle room when it comes to flood safety. Although they say they would like to store as much water as possible, they are required by U.S. Army Corps of Engineers rules to maintain a certain amount of empty “flood space” in their reservoirs, depending on the time of year.

“We don’t have an option at this point; we’re in flood-control mode,” said Kevin Dossey, a senior engineer at the state Department of Water Resources, which operates Oroville.

Dossey said the releases from Oroville won’t be enormous, clocking in at around 6,000 cubic feet per second. By contrast, he said releases during the flood of early 1997 topped 100,000 cubic feet per second.

Shasta’s releases, meanwhile, are being dialed back as the recent spell of dry weather continues. While the lake was releasing nearly 20,000 cubic feet per second earlier this week, the volume is expected to fall to around 5,000 by next Monday, said spokesman Shane Hunt of the U.S. Bureau of Reclamation, which runs Shasta.

Although the National Weather Service predicted a chance of precipitation for late Sunday, Hunt said Reclamation is adjusting its flood releases with mostly dry weather in mind. “We don’t see a major storm coming on the horizon,” he said.

Shasta and Oroville are the twin anchors of California’s giant water-delivery networks. Shasta is part of the federal government’s Central Valley Project while Oroville serves the State Water Project.

Both facilities, like most of California’s major reservoirs, are governed by the Army Corps’ “rule curves,” which specify how much empty space must be maintained at any given time during winter. The rules generally allow for a certain amount of “encroachment” into the empty space, especially if the forecast calls for dry weather.

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