Divers braving icy alpine waters replace last Oberon Dam valve

This week divers are replacing the last and deepest of the valves, working in a confined space 30 metres underwater wearing special dry suits and a large diving helmet.

“Bear in mind that each valve weighs about 400 kilograms, and only one diver can work at a time due to the tightly restricted space in the intake tower,” WaterNSW General Manager Regional Operations Sydney, Brian Mayhew, said.

“Wearing a full dry suit and helmet, the diver descends by ladder into the intake tower, and working in a confined space must undo 12 large bolts, remove the old valve which is lifted via winch operated by a team working above, who then guide the new valve down to the diver who then 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 a series of 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, and is 675mm wide and 1,500mm high. The essential maintenance project commenced last month and is due to be completed in the next fortnight.

“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 three kilometres south of Oberon on the NSW Central Tablelands, about 190 kilometres west of Sydney. At 1068 metres above sea level, Lake Oberon is classed as alpine waters.

The Fish River water supply scheme supplies water to Mount Piper power station, to 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.