HDI Lucas recently shared on its LinkedIn information about the Chatswood Sewer Amplification Project it delivered as part of Sydney Water‘s Sewerfix Program in 2003.
To this day, this project still holds one of the Australian records for an inclined bore by horizontal directional drilling (HDD) technique – 1830m in length at a 1 per cent positive grade.
The Chatswood Project comprised a network of new street sewer lines and a new sewage main which needed to be a gravity main to avoid pumping stations. Trenching was virtually impossible because the route follows Victoria Avenue, the area’s main East-West artery.
Sydney Water originally proposed a mix of HDD and microtunnelling. HDI Lucas was responsible for the design, construction, and installation.
While this would have achieved the same outcome, the community impact would have been unacceptable – requiring pits up to 17 m deep, 6 m long and 2 m wide, which would have created lengthy noise, safety, and traffic problems.
A single 1810m directional drill, eliminating the need for pits along with their risks, congestion, compensation, and liabilities, was proposed as a solution by HDI Lucas.
Although longer and more precise than any other HDD gravity sewer installation in the world, HDI Lucas was confident of its solution and provided comprehensive engineering analysis and demonstrated its experience in many of the world’s longest HDD sewer and water installations in Sydney, the Blue Mountains and Hong Kong.
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