Thatcher leak shouldn't affect industries that utilize Ouachita River water

A leak in the Thatcher Lock and Dam is set to undergo repair as soon as water levels drop to 71 feet. (Courtesy of the Union County Water Conservation Board)
A leak in the Thatcher Lock and Dam is set to undergo repair as soon as water levels drop to 71 feet. (Courtesy of the Union County Water Conservation Board)

A leak at Thatcher Lock and Dam has drained the Ouachita River to historically low levels, but Robert Reynolds, a volunteer advisor for the Union County Water Conservation Board, as well as the board's former president, said Tuesday that it is unlikely industries that utilize the Thatcher pool will be affected.

"It's my best judgment that that would not happen," Reynolds said on Tuesday. "The combination of the design of the permanent part of the lock and dam structure at 71 feet and the intentional design of the water intake structure below 71 feet would make water available to industries that use it."

Reynolds explained that the lock and dam system was built with a permanent concrete base at 71 feet above sea level. A hinged crest gate -- the part of the the dam that's currently leaking -- normally maintains the water level at 77 feet above sea level, he said; however, because the fixed concrete base is at 71 feet, water isn't expected to fall below that level.

Additionally, according to a statement Reynolds sent the Union County Water Conservation Board last week, the intake pumping system at Thatcher Lock and Dam is sufficiently submerged that it will continue to pump so long as the dam pool is higher than 67 feet, although his statement does note that the 67-foot level hasn't been tested since 2002.

Potable water for Union County residents is also not at issue, as all drinking water is supplied by the Sparta Aquifer.

"All the drinking water in Union County comes from the Sparta Aquifer. The river water is only used for industry and irrigation -- it's an excellent fluid for those," Reynolds said.

Local industries that utilize water from the Thatcher pool include the Delek: El Dorado Refinery, the LANXESS Central plant, El Dorado Chemical and the Entergy/Union Power Partners power plant, which was built at the same time as the Thatcher Lock and Dam. Additionally, Reynolds said the new El Dorado High School, Mystic Creek Golf Course, Mystic Creek residential development and Holly Falls, a local wedding venue, utilize the river water for irrigation.

El Dorado Chemical and the power plant both rely solely on the Thatcher Lock and Dam's water. Delek and LANXESS have back-up Sparta Aquifer wells.

According to the National Weather Service, at 3:30 p.m. Tuesday, the Ouachita River at the Thatcher Lock and Dam was measured at 74.14 feet. It was forecast to rise to 74.2 feet by 4 p.m. Wednesday. The pool level at the Thatcher Lock and Dam was recorded at 79 feet on Tuesday.

Local and federal officials have been notified of the leak at the dam, and the United States Army Corps of Engineers is preparing to repair the leak as soon as they're able, which will be when the water level drops to 71 feet, the level at which the hinged crest gate sits.

In a statement released last week, the USACE said there is no danger to the structural integrity of the Lock and Dam.

"Once the gate seal is exposed, USACE will perform inspections on the gate and determine what is necessary for a permanent fix. If possible, repairs will be made immediately, and the pool will be raised back to normal pool elevations," the statement said.

David Richardson, manager of Camden Water Utilities, said there are several contingency plans in place in case the water level in the Thatcher pool drops below the 67 foot pump threshold.

The first plan is to rent a water pump, place it in the river and pump water up to the intake point.

An alternate plan, which Richardson said he favors, is using an impeller -- a rotating iron or steel disc with blades -- to push water through an intake valve into the dam pool.

The third option would involve the National Guard altering the flow of the river to trap water near the intake valve.

Boating on the Ouachita River is not advised, because water levels are so low.

A leak in the Thatcher Lock and Dam is set to undergo repair as soon as water levels drop to 71 feet. (Courtesy of the Union County Water Conservation Board)
A leak in the Thatcher Lock and Dam is set to undergo repair as soon as water levels drop to 71 feet. (Courtesy of the Union County Water Conservation Board)

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