Rains push river levels up

Full-Reservoirs Tims Ford

Water spills through the Tims Ford Dam Reservoir into the Elk River as Tennessee Valley Authority (TVA) officials continue to lower the lake back to its normal summer pool level. Chuck Bach, general manager of TVA river operations, said Tims Ford Lake would likely go two feet above normal pool level due to an unseasonable amount of rain in early July.
Photo by Robert Holman

ROBERT HOLMAN, special to the times

 Mother Nature finally offered a reprieve for Middle Tennessee. After nearly two weeks of wet weather saturated the area, there was time to dry out this past week as the sun baked the region.

The heavy rains endured over the last few weeks have pushed the Tennessee River up to flood stage, while the unseasonably wet weather has had an impact on local reservoirs as well.

Despite the short dry spell, Tennessee Valley Authority reservoirs across the state are still full — that includes Tims Ford — and TVA’s water managers are spilling as much water through the dams as they safely can.

“Right now at Tims Ford we are about a foot above where we would normally be for summer pool,” said Chuck Bach, general manager of TVA river operations. “We will probably go about two feet above (before it drops). We’ve had significant rainfall across the valley. We’ve stored as much as we could. We will be releasing for a long time … maybe longer depending on if we get more rain.”

Bach said it could take 10 days or more for Tims Ford to drop back down to its normal summer pool level. With recent rains and more rain expected, the ground is saturated, meaning there will likely be more runoff.

The only place for it to go is into the reservoir and below the dam into the Elk River.

“We are getting a lot of runoff … more than normal for this time of year,” added Bach. “It’s very unusual. In Knoxville we are 19 inches above normal (rainfall measurements for the year) at the airport.”

To put that into perspective, the Tennessee River watershed has one of the highest annual rainfall totals of any watershed in the United States, averaging 51 inches a year. So far in 2013, more than 40 inches of rain has fallen in the Tennessee Valley.

“You’re feeling what everybody else is feeling across the Valley … lots of rain,” said Bach. “Unfortunately that will have some agricultural impact … some impact on farmers.”

At the time, Bach said TVA was spilling some 30,000 gallons per second through the Tims Ford Dam. By comparison, TVA is allowing 1.4 million gallons per second go through the Pickwick Dam in West Tennessee.

Unfortunately for those downstream, whether it be the Elk River, the Tennessee River or the Cumberland River — which is managed by the U.S. Army Corps of Engineers — all the waters are eventually heading the same direction. In Middle Tennessee, the U.S. Army Corps of Engineers has been holding back releases from the 10 dams it operates on the Cumberland River and its tributaries to prevent flooding.

It’s unusual to have so much rain in the summer, when TVA usually struggles to keep reservoirs full for recreation. TVA typically draws down reservoirs to their lowest levels in the fall and winter to make storage space for spring rains.

Bach’s goal now is to allow enough water to flow through the dam’s spillway gates to keep water from flowing over the dam and causing more flooding. But he also is trying to hold water back to minimize flooding downstream.

“TVA’s management of the river system is working,” he said. “TVA will spill only when all available hydroelectric-generating turbines are operating at full capacity and additional water still needs to be moved.”

Spilling along the dams is expected to last one to two weeks. As this water moves through the system, agricultural crops planted in floodplain areas along the Tennessee River in Northern Alabama and West Tennessee will be impacted by higher than normal water elevations.

“Some crop fields near the banks of the Tennessee River will see up to six to eight feet of water,” Bach said. “Crops along the Tennessee River on Kentucky Reservoir will be impacted the most.”

Some recreational areas along the Tennessee River have been temporarily closed because of high water.

 “We advise using extreme caution when near the dams, rivers and tributaries,” Bach said. “Safety is the No. 1 priority, and river currents and speed are unpredictable.”

Ironically, a year ago the same area was in the middle of a drought, as there was only 2.33 inches of rain recorded in the county during June 2012.

If there is a sliver lining this year, it’s that all of this water will likely mean lower power bills in coming months for TVA customers, although it is too early to estimate the amount. TVA hydro generation is about 40 percent above plan for the year, and the agency already has said it is lowering its total monthly fuel cost adjustment for July by 10 percent.

—The Associated Press contributed to this story.

Posted on Tuesday, July 23, 2013 at 6:19 am