Lake Levels Update

Summer’s almost gone, and with it will go some of the water in TVA’s reservoirs. We took a moment to catch up with the River Forecasting Center crew to talk lake levels as we move past Labor Day and head into fall.

SEPTEMBER 5, 2016—Let’s just say it: It’s been an off year for lake lovers. Throughout the season, lake levels across the system have been lower than normal thanks to a year high in temperatures and low in significant rain events. For much of the year, a large portion of the Valley has been categorized by the U.S. Drought Monitor as being in a moderate to severe drought.

And those afternoon thunderstorms? They’re not significantly helping, explains Tom Barnett, senior manager of TVA’s River Forecast Center. “Runoff this summer has been 56 percent of what we would normally see, and the high temperatures do not help,” he says. “When it rains, the plants take much of it because they need it…or it evaporates before it can reach the reservoir system because it is so hot.”

lake showing lower water levels

Balancing Objectives

TVA strives to keep as much water in the reservoirs as possible for recreation from June 1 to Labor Day each year. But other responsibilities are also pressing. The River Forecast Center must maintain minimum flows across the entire system—which ends in Kentucky Reservoir in West Tennessee and Kentucky—to preserve water quality; maintain aquatic life; ensure there is enough water to meet industrial, municipal, and agricultural needs; and, yes, cool TVA’s power plants, especially nuclear reactors.

To meet objectives, water has been released from the ten major tributary reservoirs above Chickamauga Dam—Blue Ridge, Chatuge, Cherokee, Douglas, Fontana, Hiwassee, Norris (picture above), Nottely, South Holston and Watauga—which has resulted in a decline in lake levels all summer long due to the lack of inflows. The tributary reservoirs are all currently in balance with each providing an equitable share of the water needed downstream.

James Everett, River Forecasting Center operations support manager, explains it like this: ”Douglas is a huge, deep lake with a 4,000 square mile drainage area. Blue Ridge is a tiny lake with only a 200 square mile drainage area. We’re pulling 20 times more water out of Douglas than at Blue Ridge, but the impact at each lake will be similar. We’re taking 2.6 feet out of Douglas this week, and only 1 foot out of Blue Ridge, but that’s equitable given the size of reservoirs.”

Go with the Flow

TVA is careful to ensure that one lake never has to bear the burden alone, according to David Bowling, general manager of River Management. Instead there is an emphasis on balancing water releases across the entire system. “But most people don’t realize each reservoir’s individual importance to the health of the entire Tennessee River,” Bowling acknowledges. “What they’d really like is for us to keep their reservoir level high by not releasing any water. What they don’t realize is that their reservoir would stagnate quickly.”

In such a scenario, “we’d have problems on both sides of the dam,” says Barnett, pointing especially to water-quality issues, which are always a particular challenge in hot years.

At any rate, Labor Day traditionally marks a turning point where boating season on TVA lakes is winding down as flood control then becomes the focus heading into the winter. TVA’s strategy to keep water levels as high as possible is replaced by the need to move water out of the system and bring lakes down to winter pool levels.

A Steady Winter Drawdown

Barnett predicts a steady drawdown throughout the system, noting the weather outlook continues to favor a dry pattern in both the near-term and long-term forecast period. “The only thing that could cause issues is if we get a tropical storm that sets up camp in the Valley,” Barnett says. The River Forecast Center will be closely monitoring tropical weather development throughout the fall, with hurricane season typically peaking in early September.

“We are still maintaining seasonal levels so that people can have access to the lakes during winter months,” Barnett explains. “But you’ll have to be careful for rocks, stumps, shoals and other hazards lying just under the surface. You’ll have to exercise more caution.”

For safety sake, Barnett recommends checking your lake level frequently in the column at right or by visiting www.tva.com.Environment/Lake Levels. While you’re on your lake’s page, check out the operating guide—this will let you see how your lake compares to last years in terms of water levels. Chances are you’ll find it’s not so bad. And definitely, it’s not as bad as it was in 2007 or 2008, which were some of the driest years in TVA’s history. “We’re not in uncharted territory here; it’s been much worse,” Barnett concludes. “Although lower than normal, we want people to continue to enjoy TVA reservoirs and remember to do so safely.”

This time next year, all this will be a memory. And hopefully, we’ll all be floating along on lakes that are full, healthy and beautiful.

 

Lake Info App

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