LITTLE HICKMAN — Work is nearing completion on the replacement of Dam No. 8 on the Kentucky River, which holds the pool from which Nicholasville and Lancaster draw their water.
The goal is to be finished before Christmas, said Daniel Gilbert, a principal and geotechnical engineer with Stantec, the consulting engineering firm on the project.
The dam needed to be replaced because water leaks through its foundation. Water escapes through underlying fissures and fractures in the limestone rock beneath the dam.
The work includes building concrete-filled cylinders, each 54 feet in diameter, in front of the old dam.
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"There is a lot of underwater cleaning work by divers to prepare the foundation," Gilbert said. "They clean out all the rocks, all the river sediment, and prepare that foundation. Then they'll place concrete in the wet. They place concrete through these pipes and kind of build up a seal that displaces the water."
The $12.6 million project is coming in on budget, said Jerry Graves, executive director of the Kentucky River Authority. That state agency maintains the locks and dams on the river.
Aquarius Marine, a subsidiary of C.J. Mahan Construction of Ohio, completed the new Lock and Dam No. 9 at Valley View. That dam holds the pool from which Lexington draws some of its water.
The Lock and Dam No. 8 project was to have been finished this summer, but high water in late spring and mid-summer delayed completion, Graves said.
During high water in April, two barges, one carrying a construction crane, drifted from the construction site and floated down the river 4 miles before stopping next to the old U.S. 27 bridge in Jessamine County. No one was hurt and there was no damage to the abandoned bridge.
Lock and Dam No. 8, nine miles south of Nicholasville, was built for $300,000 from 1898 to 1900 by a contractor for the Army Corps of Engineers.
When it was finished, the lock was able to lift a boat 18 feet, which was the highest lift of any lock and dam in the United States.
John M.G. Watt, the engineer who designed Lock and Dam No. 8, later built a lock on the Panama Canal with an even higher lift.
Lock 8 is being modified, too, in the current work. The upper gates will allow some water passage and the concrete bulwark structure will have a sluice gate to allow water through the lock chamber.
There's been talk of allowing recreation boating to go through the lock again.
"It's a possibility sometime down the road," Graves said. "Probably not in the near future."
After years of restricted access, Lock Nos. 1 through 4 (at Carrollton, Lockport, Monterey and Frankfort) reopened to weekend boating traffic on Memorial Day weekend. Some 1,700 vessels with more than 6,000 people went through those locks this year, Graves said.
"And we've actually had a terrible summer as far as high water," he said. "Lock 1 was completely shut down the whole month of July. It was completely under water. And we had a complete closure of Locks 1 through 4 for two full weekends because the water was completely over the gates."
But the lockage numbers indicate there is demand for for recreational boating.
"We've had a lot of good chatter," Graves said.
Next on the river authority's agenda is replacement of Dam No. 10 at Boonesborough, which holds the pool from which Winchester gets its water. That project is in the preliminary-design phase.