Western Sydney Recycled Water Main Project

Click to Zoom

McDonnell-Dowell-LogoThe Replacement Flows Project is part of the Western Sydney Recycled Water Initiative that consists of a joint venture between McConnell Dowell, United Group Infrastructure and General Electric (Deerubbin Water Futures) with Sydney Water as the principal client. The concept of the Replacement Flows Project is to take tertiary treated effluent from the existing sewage treatment plants at Quakers Hill, St Marys and Penrith and treat it further in an Advanced Water Treatment Plant. The Advanced Water Treatment Plant produces highly treated recycled water to be discharged to the Hawkesbury-Nepean River to replace flows of drinking water from Warragamba Dam. The St Marys plant produces up to18 billion litres of recycled water a year.  To complete the infrastructure upgrade, a total of 55km of pipeline was installed and divided into five different operating lines.


UEA were responsible for generating suitable bore designs not only to successfully complete each crossing but maintain required grades, alignments, tolerances and depth of cover. The design and construct aspect of the project enabled UEA to provide solutions that reduced restoration, minimised impact to sensitive Cumberland Plain Woodland and avoided trenching through areas of indigenous cultural significance.


Working closely with McConnell Dowell and Sydney Water, UEA successfully constructed the majority of trenchless crossings on the Replacement Flows Project using Horizontal Directional Drilling.

  1. Eastern Creek crossing – 83m of parallel 400mm and 560mm
  2. Quakers Hill Parkway crossing – 60m of parallel 400mm and 560mm
  3. Palmyra Avenue, Lethbridge Park – 60m of parallel 400mm and 560mm
  4. Old Windsor Road, Seven Hills – 144m of 355mm
  5. Church Street, Parramatta – 116m of 355mm
  6. Pennant Hills Road, Oatlands – 70m of 355mm
  7. M7 Motorway crossing, Dean Park – 345m of parallel 355mm and 560mm
  8. Lalor Creek, Seven Hills – 87m of 355mm
  9. Powers Road, Seven Hills – 80m of 355mm
  10. Prospect Highway, Seven Hills – 384m of 355mm
  11. James Ruse Drive, North Parramatta – 133m of 355mm
  12. Bells Creek/Richmond Road crossing, Dean Park – 300m of parallel 355mm and 560mm
  13. Sunnyholt Road, Blacktown – 110m of 355mm

Due to exacting grades, difficult access, busy arterial roads and requirements of pinpoint accuracy, the use of Paratrak HDD guidance technology was required on four crossings – these locations were underneath the newly constructed M7 motorway, the busy intersection of Old Windsor Road and Powers Road, Prospect Highway from Seven Hills train station to Powers Road and a crossing of James Ruse Drive exiting parallel to the Caltex multi products pipeline.

For more information about this project or UEA Trenchless, please send enquiries to Steven Hopkins.