A 6-inch decision could add a decade, or more, to Catawba River’s lifespan

It’s only 6 inches of water. Until it stretches over 53,000 acres. Then, it’s drought insurance.

Not to mention another decade or so for the Catawba River’s ability to support drinking water, electricity production and other needs in the region.

The Federal Energy Regulatory Commission published a notice July 20 after Duke Energy requested changes to its hydroelectric license to operate along the Catawba River. The notice began a 30-day period for public comments, motions and intervenors in the decision.

Among the changes is a request to raise the target water elevations of three lakes — James, Norman and Wylie. Duke would aim to keep each 6 inches higher May 1-Oct. 1 annually.

“Raising reservoir normal target elevations by 6 inches on our three largest storage reservoirs increases available storage by approximately 8 billion gallons,” said Kim Crawford, company spokesperson.

Duke’s license impacts all 11 reservoirs on the Catawba River in 14 counties spanning both Carolinas. Lake Norman is by far the largest at 32,475 acre, and nearly as big as the other 10 combined. Norman provides 40 percent of the usable water in the system.

James, the headwater lake, is much smaller at 6,812 acres, but it’s deep. It provides about a quarter of the system’s storage.

Wylie covers 13,443 acres and serves Catawba Nuclear Station and most of York County with drinking water.

“These increases represent access to a greater volume of water during typically drier summer months than is currently available under the existing target elevations,” Crawford said.

They also help solve a problem Duke and municipal water providers along the Catawba discovered throughout a hydroelectric relicensing project dating back more than a decade. A study found the amount of water needed from the Catawba — drinking water, power, the whole lot — would exceed what it yields by 2048.

Further studies began, largely from the Catawba-Wateree Water Management Group made up of Duke and municipal suppliers, on how to extend that deadline. Conservation and drought management were discussed, as well as lowering or moving public intakes.

Another 8 billion gallons of water certainly could help.

“Modeling results indicate this strategy alone could extend the water yield of the Catawba-Wateree lake system by one decade beyond current conditions,” Crawford said. “Combined with other strategies recommended in the water supply master plan, this strategy will help extend the system water yield by an additional 40 to 50 years beyond current conditions.”

For many, it wouldn’t take nearly that long to see the impact of more water. Six inches of water can be the difference in lakefront homeowners accessing their boats. It can be the difference between public boat ramps closing or staying open, or lake event like Riversweep or Christmas boat parade going off as scheduled.

At least some level of drought, from watch to severe, happens every year. Boat ramps on Lake Wylie were closed because of low water for part of 2015 and 2016. Ramps also closed in 2007 and 2002.

The region only recently downgraded its drought status to a watch stage. Lake Wylie Marine Commission member Brad Thomas recently asked what Duke can do when it rains to ward off problems when it doesn’t. He understands hot summer days with little rain strain the system.

“We’re just asking you to anticipate that,” Thomas said.

Ronnie Lawson, who works in lake services for Duke, said there are several factors to how high a lake sits. Rain is only part of it.

“These 95-degree days, you have millions of gallons of evaporation,” he said. “That’s where most of your water goes.”

Power plant evaporation is another major factor, as are public drinking intakes.

The target level for lakes isn’t an exact fill line. Even in normal rain patterns the lake level can sit a few inches off the target. Targets are several feet higher than critical low points where intakes are exposed, and a few feet lower than full pond where flooding becomes a concern.

Duke’s request was agreed upon by its relicensing stakeholder group. The water management group supports it. It’s part of new water quality certifications issued by North and South Carolina.

Other parts of the request include reducing recreational water flows from the Wylie Hydro Station by half —from 6,000 to 3,000 cubic feet per second — and updating the regional protocol for drought response.

Federal regulators don’t have a deadline on the decision, Crawford said.

“The time may depend on how long it takes them to address comments received during the public notice period,” she said.

This story was originally published July 30, 2017 at 5:47 PM with the headline "A 6-inch decision could add a decade, or more, to Catawba River’s lifespan."