CHARLOTTE -- Duke Energy, for the first time, put a date Tuesday on when Catawba River communities could begin to gasp for water: mid-March.
That's when the shallowest water intakes on Catawba reservoirs would have too little water over them to pump normally.
At that point, the region's water supply would be increasingly tenuous, likely prompting a shift from conservation to emergency measures."Our position is that when the first intake goes, it affects us all," said Maeneen Klein, conservation coordinator for Charlotte-Mecklenburg Utilities.
Duke, which manages the Catawba under a federal license, says the March projection is based on worse-than-likely circumstances. While many cities pull water from a single reservoir, the Charlotte region uses a more complex system that moves water among 11 lakes covering 225 river miles.
Duke, unlike the water systems serving such cities as Atlanta and Raleigh, has resisted estimating when water in the Catawba would run short.
Now, Duke says, Catawba communities need to know when they might have to take major steps to keep taps flowing. Duke announced its projection at a meeting in Huntersville, N.C., with water systems that draw from the river.
Once their intakes become threatened, some communities would have to buy pumps or move intakes. That takes time, to place orders and apply for permits.
The Gastonia, N.C., emergency plan would take several months to put in place, said city water official Ed Cross.
If no rain falls by year's end, the city would rent a large raft, mounted with pumps, to draw water from deeper parts of Mountain Island Lake. Flexible pipes would move the water to the city's intake, which supplies 100,000 people.
Lake Norman's level Tuesday was 3.4 feet above its shallowest intake, which serves a Duke power plant. Mountain Island Lake was just inches above another power plant intake. Lake Wylie was less than a foot above its shallowest intake, an industrial pipe.
The March projection is based on a "near worst-case" scenario that Duke says is unlikely to play out. It assumes that water stored in the Catawba reservoirs will continue to drop 2 percent a week, its rate since late August. It also assumes that recent rainfall patterns, which have left Charlotte nearly 13 inches below normal for the year, will continue.
Federal forecasters predict a drier-than-normal fall and early winter. But the National Weather Service's Climate Prediction Center says there is only a 10 percent chance that conditions will remain as dry as they have been this summer and fall.
The forecast also doesn't take into account tighter water restrictions -- Stage 4 -- that Duke says will likely take effect if no substantial rain falls.
The 1 to 3 inches of rain that fell on the Catawba basin last week will likely delay Stage 4 restrictions to mid-December to mid-January, Duke said Tuesday. That's about a month later than the company had estimated earlier.
Charlotte-Mecklenburg has said it could consider adopting tougher restrictions before Duke declares Stage 4. The restrictions could include a ban on all outdoor watering, with no exceptions, and higher fines.
Even with more rain, Klein said, the lawn irrigation ban now in place isn't likely to go away soon. "We certainly don't want to pull out of everything and then turn around and go right back into it," she said.