A major programme of work is underway on the four highest locks at the Caen Hill Flight on the Kennet and Avon Canal.
Workers from the Canal & River Trust, the charity that cares for the flight, will be relining the lock gates and repairing brickwork in lock chambers that date back to the early 1800s.
The Caen Hill Flight, at Devizes, Wiltshire, is described as one of the ‘wonders of the waterways’ – with 16 locks that form a giant watery staircase to allow boats to travel up and down the steep hillside.
As part of the work, the adjacent side reservoir ponds – used to store water to operate the locks – must be drained to around 0.5m deep.
This allows the engineering team to descend the 5.5m or 18ft into the locks to repair the brick work, using traditional lime mortar in keeping with the locks’ heritage.
The lock gates, bumped and scraped by the estimated 1,500 to 2,000 boats that travel through the flight each year, will be relined using traditional green oak.
Mark Evans, director for the Canal & River Trust for Wales & South West, said: “We are proud custodians of Caen Hill Flight.
“As a Scheduled Ancient Monument, it enjoys the same level of heritage protection as Stonehenge – so it’s a big responsibility.
“This year the Trust is spending £70k on the repair work at Caen Hill to allow the thousands of visitors, on boat and on foot, to continue to enjoy this very special place.
“The flight is iconic for so many reasons. It’s a massive feat of engineering from the heyday of the canals and one of the country’s longest continuous runs of lock flights.
“It’s also the ultimate challenge for many boaters – demanding four hours to travel up, or down.
“Such is the challenge that we have a team of lock keepers, many of them volunteers, to assist. And those volunteers also help to care for the canal and towpath.”
Mr Evans said the work, which is being carried out within coronavirus guidelines, was “crucial” to keep the flight in peak condition.
The towpath at Caen Hill remains open and the flight is planned to reopen to boats on March 19.