(Editor’s note: This is from TVA’s PR department. Check here for video of a boathouse crashing into a dam and coming out the other side in small chunks.)
February’s massive rains washed tons of debris into the Tennessee River system … and directly toward some of TVA’s dams.
During the wettest February in recorded history, the Tennessee Valley Authority held back more than 3.5 trillion gallons of water to help prevent over $1.6 billion in flood damage across the Tennessee Valley.
The raging waters and record rainfall caused extensive erosion along Tennessee River banks. Also, the rising water in the system washed tons of debris onto shoreline properties, recreation areas and even into TVA dams.
Trees, logs, docks, trash and other debris were torn away and washed miles downstream, scouring and littering shorelines and clogging trash gates at some TVA dams. The deluge of debris impacted or threatened generation at several dams, at a time when massive amounts of water were being pushed through the dams to prevent flooding. For example, Pickwick Dam in West Tennessee was releasing 4 million gallons per second at its peak flow.
TVA crews worked 24/7 to overcome debris disruptions to provide reliable power throughout the deluge.
Dam safety inspections are still underway and will continue until heavy rains, lake levels and river flows subside.
Ben Phillips, manager of dam safety inspections, said technology such as side-scan sonar will be instrumental in evaluating spillway aprons.
“We can get a look at a spillway in a few hours per dam using sonar compared to a few days or weeks per dam using divers, with less safety risk,” Phillips said.
TVA has contingency plans for all its dams in the event of emergencies such as severe weather like the recent record rainfall, and it works closely with emergency management teams to prepare for these events. TVA also has spent about $400 million since 2010 on dam safety.
In addition to inspections after severe rain events, TVA also performs monthly, biannual and annual inspections of its hydro facilities to identify any potential issues or concerns and detailed, thorough investigations every five years. The inspections also include continuous electronic monitoring for vibrations, and rigorous structural and geological assessments.