Client: Cardinia Council

Project Summary:

Afflux Consulting was engaged by Cardinia Shire Council to investigate the capacity of the minor drainage system at the intersection of Rossiter Rd and Station St, Koo Wee Rup. The hydraulic capacity of key pits where flooding and spilling is known was modelled. The area is highly developed and forms the junction for key roads in Koo Wee Rup. The region grades north-east to south-west and eventually discharges to Western Port Bay.

A range of hydrological and hydraulic measures were trialled to provide Council with several mitigation options. A key factor to spilling observed is the shallowness of the crossing at Station St, and can be addressed by increasing the capacity of downstream pipes. The degree to which this should be undertaken was dependant on resources and funding available.

Project Recommendations:

Four flood mitigation options were presented to council as the result of extensive hydraulic modelling in DRAINS. Ultimately, pipe sections along the south-side of Rossiter Rd were to be diverted and connected to the 900mm dia system further down the road, rather than re-entering the Station St system as was the existing case.

Council was also advised to upgrade existing underground structures to allow efficient collection of stormwater in the minor storm. This was the result of CCTV showing broken pits and pipes in some locations in the network.

Key Features and Innovations:

  • CCTV used to determine applicable blockage factors for the hydraulic model.
  • Applying Urban ARR2019 to DRAINS modelling.
  • Modelling many solutions and surrounding drainage networks.