The Corps of Engineers says Newt-Graham Lock and Dam 18 on the McClellan-Kerr Arkansas River Navigation System has returned to full operation following a number of repairs to the down-stream gates.
The Corps says it had been monitoring leaks in the gates for several months and decided to drain the water out of the lock to find the cause.
"When the lock was dewatered, a number of additional repairs showed up that needed fixing to avoid future unscheduled shut downs," according to Johnny Bell, Tulsa District Technical Support Branch Chief for the U.S. Army Corps of Engineers.
The Corps says it suspected one of the problems was the rubber seal on the bottom of the miter gate. "Dewatering" the lock confirmed that the seal was damaged. In some places it was torn loose.
Debris had jammed against the concrete sill and the seal's backing plate, according to the Corps, causing large gaps.
"You never fully know the extent of damage or repairs that are needed until the chamber is emptied. That is why we plan for scenarios A thru Z and ensure our team is prepared for anything," said Rodney Beard, Tulsa District Navigation Project Manager.
Early on in the process of dewatering the lock, the repair crew discovered more damage. Debris had damaged a portion of the steel girder in a high stress area of the miter gate.
The repair required cutting out the damaged section and welding in a new piece. Before the repair could be made, the 185-ton gate had to be supported with hydraulic jacks. Other repair work that had already been scheduled had to be postponed while the gate was immobilized.
Fixing the unexpected damage delayed reopening the lock by two days. But the Corps says it was worth it.
"With the damages discovered during the dewatering, the time required to complete the additional repair work was time well spent to help assure future uninterrupted operations of an important part of our nation's infrastructure," said Col. Richard Pratt, Commander, Tulsa District, U.S. Army Corps of Engineers.