Rising Kerr Lake level exceeds 303 feet

Jan. 21, 2013 @ 07:19 PM

Residents of localities along the Roanoke River basin can breathe a sigh of relief from drought conditions at Kerr Lake as levels rose to a generous 303.25 feet by Monday morning.

Water was still rising with projections for a 303.7-foot level today. Voluntary conservation measures requested by local governments are not known to have been formally rescinded, but are expected.

Army Corps of Engineers increased release volumes to 14,000 cubic feet per second, and plans were for that to go to the 20,000 CFS level called for as water levels increase above the 300-foot point where the flood pool rates begin.

Engineers were happy to see the rain, and said there was no danger of actual flooding locally: it is at 306 feet that the level begins to impact some low-lying roads and camping or picnicking areas at Kerr Lake. Household structures are regulated for construction at 321 feet or higher.

The engineers and lake recreation leaders like to keep lake levels at a 295.5-foot “guide-curve” point during the winter, according to Chip Harris, a Kerr-Lake shift operator with the engineers.

“Over the next seven days, we are predicting a level at about 300 feet, give or take,” Harris said. “Our lake is up about 10 feet because of this recent rain event.”

The draw-down from nearly 304 feet is a man-made response of increasing releases and power generation throughout the Roanoke River Basin system.

Tony Young, a manager with the Kerr Lake water management system, said release volumes are likely to get an upward bump again. The goal is to draw down to about 300 feet, then regulate so levels will be at a 302-foot level in April.

“We have already increased our releases to 14,000 CFS, and we may increase our releases again,” Young said. “A 300-foot level is the bottom of our flood pool.

“We have been dry for so long, it was good to see all the rain,” he added. “It was pretty wide spread, certainly across the Roanoke watershed into Virginia, and it was across the state also.”

Young said that the sustained rainfall was good for water levels of all types, including underground for well-water users.

“It was a good rain, right where we needed it,” he said. “Rain like this was needed.”

Young said flooding is not a danger from recent rain, but in rare flooding events the Kerr Lake system is capable of releasing up to 35,000 CFS. For example, if water levels reached extreme highs such as 312 to 315 feet and covered roads and lakeside recreation areas, even endanger some structures near the 321-foot level, water could be released.
The recent rain held out no such threat.

“There was a lot of storage available since the lake was low,” Young said.

In December, localities implemented voluntary cutbacks of water usage because lake levels were so low, dipping below a 294-foot point that causes drought measures to begin. Levels were at about 292 feet, according to Dec. 13 reports.

Lows become a substantial concern at 289 feet, where mandatory conservation kicks in. At 285 feet, a water shortage emergency would be declared, and localities implement rationing measures if the lake reaches the 280-foot level.

Lake levels have not gone below the 291-foot level during the recent life of the lake except for during a 2002 water-level emergency in which lake levels dipped below a 285-foot level needed for the water intake system at the Kerr Lake Regional Water Plant.

A 20,000 CFS release rate calculates to about 9 million gallons of water every minute, according to prior reports.

Contact the writer at mfisher@hendersondispatch.com.