All the heavy lifting has been done – literally – on a major infrastructure upgrade to the Lake Buffalo dam.
Goulburn-Murray Water (GMW), in partnership with contractors Global Factory Maintenance, this month successfully finished replacing all three steel gates in the dam’s concrete spillway. The lifting mechanisms used to control the gates were also replaced with modern equipment meeting contemporary safety standards.
“Last year we removed, refurbished and replaced the first gate and now we’ve replaced the last two,” GMW Managing Director Pat Lennon said.
“It was the first time since 1965 these gates have been removed from the concrete spillway structure, so more than 50 years of reliable operation has been a good run,” Mr Lennon said.
“Over that period of time there’s been some erosion and wear on the gates so we’ve had them sand-blasted and sprayed with a new, high-tech epoxy coating. At the same time, we’ve had new walkway and lifting hoists custom-made to comply with today’s occupational health and safety standards.”
Managing the $3 million project has had its challenges – not least of which was removing structures that normally hold back 24,000ML of water. To allow for the works, Lake Buffalo was drawn down to about 40 per cent of its capacity during the last two winters to keep the water level below the lip of the spillway.
The gates’ removal involved dismantling electrical cabling and steelworks that have been in place before most of workers involved in the upgrade were born. The sheer size of the gates and platforms required the use of a 90-tonne crane with its weight carefully distributed over the concrete pylons of the spillway structure.
The gates themselves – each weighing 12 tonnes - were lifted clear of the dam, carefully swung overhead and then lowered more than 30m onto the concrete spillway. Here they were laid flat, re-attached to the crane, lifted clear and placed on a flat-bed trailer.
The steel gates went to Melbourne for refurbishing while the platforms and hoists were designed, pre-fabricated and tested at the contractor’s Wodonga factory. Remaining metal infrastructure bolted onto the concrete dam was sand-blasted and recoated on-site after first being encased in plastic sheeting, to prevent any environmental contamination.
Replacement of the structures was essentially the reverse of removal, with the addition of high-tech electrical infrastructure like touch-screen operation and modern recording and back-up systems.
GMW Regional Customer Service Manager East Martina Cusack said it was gratifying to have met the supply needs of irrigators and urban water users while the works were underway.
The road over the dam has re-opened to single-lane traffic while final installation, testing and commissioning of the new equipment takes place this month. Ms Cusack thanked residents and recreational users of the lake for their patience during the short periods of road closures required over the last two years.
“We now expect to get continued reliable service from Lake Buffalo for a long time to come,” Ms Cusack said.
The dam was originally built to serve a thriving tobacco industry by delivering irrigation water into the Ovens Valley via the Buffalo River. The dam now delivers water critical for dairy, cropping and vineyard enterprises and for urban supplies to high country towns like Myrtleford.