Reservoir operations update
Dry conditions affect outlook for summer reservoir levels
TVA’s Randy Kerr is hoping for some wet weather in the next few weeks. “We got some much needed rain in early April, but we’ll need a lot more to hit the June 1 targets for the summer recreation season on some tributary reservoirs.”
As Manager of River Forecasting at TVA, Kerr keeps a close eye on rainfall and runoff — the amount of water that reaches streams, rivers, and reservoirs. “We’ve had about two and half inches of rain so far in April, but we’re still six inches below normal for the past seven months. Rainfall in February and March, which are typically the wettest months of the year in the Tennessee Valley, totaled only 4.9 inches, the second-lowest total for those months in 117 years of record. Runoff totaled only three inches, the fifth-lowest in 132 years of record.”
TVA is operating the reservoir system in a water-conservation mode because of the lack of rainfall and runoff, says Kerr. “We began restricting releases from tributary reservoirs in late February, and since late March we’ve only provided minimum flows. We’re continuing to meet water quality and water supply needs, but we aren’t releasing any additional water for hydro generation, above the required minimum flows.”
So when are the tributary reservoirs likely to fill this year? It all depends on rainfall and runoff in the weeks ahead, according to Kerr. “We’re well into the spring growing season, so there’s less runoff. When it rains, more water is absorbed by the vegetation before it reaches the reservoir system. So we’ll need sustained, soaking rains in late April and May to reach summer pool levels on June 1.”
If the reservoirs don’t reach target levels, it won’t be from lack of effort on TVA’s part, says Kerr. “Unless there’s a power system emergency, we’ll continue to restrict releases through the summer as long as the volume of water stored in tributary reservoirs is below minimum levels. We want to fill these reservoirs as much as anyone.”
Higher pool levels make TVA’s job — balancing the use of the water for multiple purposes — a lot easier, explains Kerr. “Besides the benefit to reservoir users, it gives us more water for releases to protect water quality and water supply — especially releases to provide water for cooling our fossil and nuclear plants. It helps us meet the requirements for providing recreational releases below our dams. And it enables us to generate more low-cost, clean hydropower.”
To check your reservoir’s current elevation and see predicted elevations for the next three days, go to TVA’s Reservoir Information page; then find the name of your reservoir in the pull-down menu and select “Releases and Elevations.” View a graph comparing normal and observed rainfall and runoff for the eastern Valley.
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