Spillway gates at Thurmond sub-basin are currently undergoing repair on a number of areas where pitting has developed on the surface of the gates.
The gates are armored with industrial grade coating, which typically lasts 30 years, to protect them from the elements. Periodic maintenance prevents the pits from getting past the industrial coating into the gates, said Scott Hyatt, Thurmond Lake operations project manager.
“The previous coatings reached the end of their useful lives and some of the gate components started to deteriorate,” said Hyatt.
Original restoration work, funded under the American Recovery and Reinvestment Act of 2009 (also known as the Stimulus Plan), began in 2009. It included inspecting and repairing critical welds and applying a layer of a fresh protective coating to the gates, arms and lifting equipment, said Hyatt.
Initial work concluded in 2012, but a second round of funding appropriated by Congress permitted pitting repair to continue in late 2013, said Hyatt.
Construction Services Group, Inc. and their subcontractor, Augusta Industrial Coatings, are scheduled to complete maintenance in the spring of 2015, said Hyatt.
In the interim, reservoir levels at Thurmond Lake must be held one foot below full summer pool – 330 feet above mean sea level – until the completion of gate maintenance, said Stan Simpson, the Corps’ hydrologist.
Levels above 329 ft-msl pose a danger to workers. “If lake levels rise above 329 ft-msl, windy conditions can cause lake water to overtop the bulkhead and damage scaffolding and equipment,” said Hyatt. “Should the lake rise to this point before work is complete, the lake would be held at this elevation.”
Upkeep for the spillway gates is important because the gates are vital to balancing the basin. If lake levels rapidly rise and exceed the design storage of the project, opening the gates prevents water from overtopping the dam, said Hyatt. During periods of intense downpours, water can be released from the reservoir without passing through the hydropower plant, and without causing damage to the dam.
~Chelsea Smith, Public Affairs Specialist