Surprise Downpour Disrupts Wilson Lock Repairs
An unexpected storm dumped 6 to 7 inches of rain near where crews are working to repair the main navigational lock at Wilson Lock and Dam on the Tennessee River, forcing equipment to be pulled from the lower end of the chamber to avoid potential damage.
“This weekend was massive rainfall that was not predicted,” said Nikki Berger, navigation program manager for the Tennessee Valley Authority. “All storms are not predicted, and this one certainly was not in the forecast.”
A caisson set on the lower end when the chamber is dewatered narrowly avoided being overtopped March 16, which would have required an inspection and resulting delays, said Meagan Simpson, chief of the maintenance section for the Nashville Engineer District. Simpson led a weekly videoconference March 18 for industry stakeholders.
“The lower closure structure is still set, and at this point we are waiting for the tailwater to recede before we can begin work again,” Simpson said.
A minimal amount of contingency time for weather delays was included in the schedule to replace cracked components in both lower miter gates at the lock, Simpson said. However, she said if work can resume quickly, she believed the project could stay on schedule to reopen June 14.
She believed it might be possible for equipment to be placed back into the lock by March 20.
“As soon as the tailwater recedes, we will pump the chamber out and get back to work,” she said.
Simpson said work needed to install gate supports and guides to make it possible to jack the gates had continued “so work hasn’t come to a complete halt.”
The lock has remained closed since September 25, when lock operators heard popping noises that turned out to be cracking in the pintles or hinges used to swing the lower miter gates open and closed, along with the gates’ bottom girders.
Brian Brewer, facility operations supervisor, noted some recent issues at the auxiliary chamber, which can transit one standard-sized barge at a time. A lock line had to be pulled out in one instance to keep it from getting snagged on boats, he said, halting traffic for a time. In another, he added, a boat that had waited in the queue for two weeks was moved to the back of the line again after it was determined there was not sufficient crew on the boat to transit the lock. He reminded those representing companies with boats transiting the lock to make sure those boats remained crewed so that they could immediately move when called upon to do so.
