Specialist divers braving the icy waters of Lake Oberon for the past month have nearly completed valve replacement in the dam’s intake tower, each valve weighing almost half a tonne.
Divers are replacing the last and deepest of the valves. They work in a confined space 30m underwater, wearing special dry suits and a large diving helmet.
WaterNSW’s General Manager of Regional Operations Sydney, Brian Mayhew, said, “Bear in mind that each valve weighs about 400kg, and only one diver can work at a time due to the tightly restricted space in the intake tower.
“Wearing a full dry suit and helmet, the diver descends by ladder into the intake tower. Working in a confined space, they must undo 12 large bolts and remove the old valve lifted via a winch operated by a team working above. That team then guides the new valve down to the diver, who re-screw 12 bolts.
“It’s a highly specialised operation, and we take every safety precaution to keep our staff and contractors safe.”
Divers have been replacing valves along a vertical section of the Oberon Dam intake tower. The valves control the release of water from the dam as part of WaterNSW’s Fish River supply scheme that supplies Oberon and Lithgow councils.
Each valve weighs about 400kg, is 675mm wide, and is 1,500mm high. The essential maintenance project commenced in August and will be completed in the next two weeks.
“The water temperature has been a chilly eight degrees, but these specialist divers wear dry suits and do this kind of work year-round,” Mr Mayhew said.
“The work will help ensure the reliable and efficient operation of the Oberon Dam intake tower and safe water supply to customers in the Fish River region.
“WaterNSW invests in regular maintenance and upkeep to ensure the reliability of our assets into the future and provide the best outcomes for our customers.”
Oberon Dam is situated on the Fish River about 3km south of Oberon on the New South Wales Central Tablelands, about 190km west of Sydney. At 1068m above sea level, Lake Oberon is classed as alpine waters.
The Fish River water supply scheme supplies water to Mount Piper power station, Oberon and Lithgow councils for domestic and industry use, and to about 230 properties along its length. It also supplements town supplies in the upper Blue Mountains.
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