Repair work has stopped temporarily at Hebgen Dam as PPL officials look into causes behind high readings on gauges monitoring the stress levels on the temporary cofferdam used in the construction process.
“We had a problem with the gauge readings in the cofferdam that measure strain,” said David Hoffman, spokesman for PPL.
However, inspection of the cofferdam hasn’t shown any structural problem with the dam and so PPL officials are trying to sort out whether the readings were accurate or if the gauges had malfunctioned.
The elevated stress readings were discovered last Tuesday and work on the dam was suspended then, Hoffman said.
The repairs at Hebgen Dam stem from a 2008 incident where the century old boards used to operate the intake structure failed and left PPL without the ability to completely control the water coming out of the dam.
To fix the problem, PPL installed a cofferdam to dry up the intake structure and allow crews to rebuild the old intake operations and bring them up to a more modern level.
“The cofferdam retains the water in the lake and gives workers access to normally submerged portions of the intake structure, allowing them to work on the permanent repairs,” according to a statement released by PPL. “The intake structure and the dam are stable.”
The work on Hebgen Dam is scheduled to be done by 2014, Hoffman said. But pinpointing an actual date isn’t possible at this point.
One of the struggles in working at Hebgen Dam, which is on the upper Madison River, is the short construction season. But despite this current setback, Hoffman said the 2014 completion date is still accurate.
However, he’s not sure when work will resume this year.
“For the rest of the season, I guess I don’t have an answer when we’ll get back in there,” he said.