TVA Managing Flows from Record Rain

Record rains hit the Valley over the past weekend, causing a flurry of activity for TVA's River Forecasting Center and helping to offset the effects of the Valley's long-term drought.

APRIL 25, 2017—TVA’s River Forecast Center in Knoxville is continuing flood operations and managing lake levels to minimize downstream flooding after record rainfall and heavy runoff over the past weekend, especially in the eastern part of the TVA service area.

The National Weather Service (NWS) reported record daily maximum rainfall in Knoxville for the date of April 23, with 1.97 inches breaking the old mark of 1.67 inches set in 1977. NWS also reported record rainfall for the date in the Tri-Cities, which received 1.87 inches to surpass the old record of 1.32 inches set in 1968. Chattanooga also totaled 1.87 inches on April 23, while Nashville peaked at 2.67 inches on April 22.

TVA’s Fort Loudoun, Watts Bar and Chickamauga reservoirs on the main stem Tennessee River will rose above summer pool levels, a couple of weeks ahead of normal summer pool schedule. TVA also will be spilling at seven of its nine main stem dams this week.

Tributary lakes like Norris, Cherokee and Douglas also are all seeing higher than normal water levels, with some already near normal summer pool.

While concentrated in the east, total rainfall averaged about 4 inches across the valley, with over an inch of runoff, for the 2-day period between April 22 and April 23.

After seeing drought conditions most of last year, the Tennessee Valley is now trending ahead of the normal rainfall pace for the calendar year, with a total of 18.5 inches representing a surplus of about one inch. Runoff is still running a deficit for the year at 8.5 inches or about 68% of normal due to lingering effects from the drought.

Rainfall totals and their variances from normal thus far in calendar year 2017 in cities across the TVA service region include:

  • Chattanooga: 21.73 (+3.93)
  • Knoxville: 18.59 (+2.63)
  • Tri-Cities: 14.08 (+1.29)
  • Huntsville: 15.69 (-2.52)
  • Nashville: (15.43 (+0.96)

To create storage capacity and as much hydropower as possible, TVA is moving the waters down the system. TVA is currently at maximum turbine capacity and spilling excess water at Kentucky Dam at a rate of 1.1 million-gallons-per-second.

TVA also is working with local media, communities and other groups to notify the public of high water levels and flood risks, and alert fixed dock owners to consider moving boats out from under dock roofs and remove anything that might float.

Get real-time information at our Lake Level page and the free TVA Lake Info app.