Drilling work to construct seven 450 mm diameter underground holes, to reach 200 metres into the Bay, has started on Anzac Parade in La Perouse.
EnergyAustralia’s Kurnell and Bunnerong subtransmission substations will be connected by seven kilometres of 132,000 volt cable to improve the power supply to 61,000 homes and businesses in Sydney’s inner suburbs and CBD.
EnergyAustralia General Manager of Engineering Geoff Lilliss said that every stage of the project has been carefully planned and communicated to the community via 6,000 newsletters.
“We’ve prepared a seagrass management plan with the Department of Environment, Conservation and Climate Change and the Department of Primary Industries to make sure the seagrass will be protected,” Mr Lilliss said.
“We have also employed a marine ecologist, who helped develop the seagrass plan and will continue to closely monitor the Bay both during and after the work is completed.
“An independent seagrass expert from the NSW Department of Primary Industries will also review our work, step by step, across the seagrass bed.”
During installation, the seven cables will be suspended on top of the water with buoys and then lowered by divers to rest on the sea floor across the Bay, approximately five metres apart.
A water jet will travel over the length of each cable, gently burying it into the sea bed.
Where the cable route crosses the seagrass beds, the cables will be joined to create two bundles, laid onto a separate track and carefully buried by the specially designed water jet.
Work to lay cables in the Bay is expected to start in September 2009.
Mr Lilliss said that the cables needed to be buried a safe distance below the sea floor to allow for the future widening of the Botany Bay shipping channel.