Mile Creek Sewer

Noble Park, Vic

Project Duration

January to December 2023

Client

South East Water

Project Value

$ 10m

The Mile Creek Sewer Project represents a critical upgrade to increase sewer capacity within the South Eastern suburb of Noble Park as booming property development and population growth has led to an
overburdening of the existing infrastructure. Zinfra-Jaydo-WSP (ZJW) Joint Venture, on behalf of South East Water, was awarded the contract to execute the sewer upgrade, beginning with early concept designs through
to detailed design, supply, construction and commissioning of the new gravity sewer.

To deliver the works, ZJW elected to utilise trenchless methodologies, micro tunnelling between shafts and installing the pipe via pipe jacking. This method minimises the impact on the surrounding public and reduces the natural resource requirements of the project.

Scope of works:

Design of new gravity sewer
Installation of ~2.6km of DN300 Glass Reinforced Plastic Pipe via trenchless methods
Installation of ~300m of DN450 Glass Reinforced Plastic Pipe via trenchless methods
Construction of 36 new sewer manholes
Modification of existing manholes

key challenges

Coordination of traffic management around work zones to ensure minimal impact to local stakeholders
Construction within suburban streets with extensive existing infrastructure; Power (overhead & underground), sewer, water, gas and communications
Variable ground conditions with ground water present throughout

key innovations

Development of relief sewer concept:
- The initial design concepts were to replace the existing sewer with a larger diameter pipe via pipe cracking, or to install a detention tank along the alignment to accommodate high flow events
- ZJW offered the relief sewer concept:
  - Creating superior capacity along the alignment
  - Intercepting existing sewer infrastructure at critical surcharge locations
  - Saving cost compared to costly pipe cracking
  - Including new maintenance structures for future connections
Utilisation of Modular Shoring Systems for deep excavations (>8m):
- Allowed for construction of deep shafts beneath powerlines and critical trees where traditional shoring systems (trench shields / sheet piling) would not have worked