We're rectifying water levels of the Thornhill Park Retarding Basin and Wetland so that we can finish the landscaping works and plantings around the park, while reducing the risk of flooding to surrounding homes.

Why this is important

In Melbourne, rain and storms are part of everyday life. Floods are a natural part of our landscape and an essential part of the weather cycle. Melbourne Water manages more than 200 retarding basins. They are designed to reduce flooding by catching heavy rainfall which hold in a reserve of low-lying land. Once storm water is collected, it is naturally treated within this system prior to being slowly released back into the environment to follow the natural drainage lines into our creeks, rivers and eventually to the bay.

About the project

The Thornhill Park retarding basin will reduce flooding events and keep our community safe today, tomorrow and for generations to come.

Project status

In 2018 works to establish a retarding basin at Thornhill Park Estate were undertaken by the developer of the site. After the site was handed over to Melbourne Water to manage, it was determined a drainage channel needed to be constructed north of the Western Freeway. The new channel will help to maintain storm water flow towards nearby wetlands to ensure stable and consistent water levels in the retarding basin. Landscaping works have been deferred until the channel is constructed so that the water level of the retarding basin could be lowered to an appropriate and consistent level to allow for civil works to be completed and plants to establish effectively.

Once the water levels are dropped channel works on the northern side of the freeway will be completed, allowing remediation and landscaping works to commence.

What will the works involve?

The works will be undertaken in two stages, firstly;

  • Installation of ‘hard’ landscaping, including a fitness area, viewing platform, boardwalk and paved areas, and secondly,
  • Installation of ‘soft’ landscaping, which includes planting over 190,000 plants covering the terrestrial and aquatic zones in and around the wetland system

Location of the Thornhill Park retarding basin

The retarding basin is located near Paynes Road and the Western Freeway and can be accessed from Wingfield Drive and Gilfillan Circuit in Thornhill Park.



Works on retarding basin commenced




Developer hands over management of Thornhill Park Lake retarding basin to Melbourne Water and further investigations are undertaken to determine additional significant drainage works required to direct storm water flow to Kororoit Creek



Heavy summer rain – project deferred until water levels can be reduced

Not Started


Installation of ‘hard’ landscaping

Not Started


‘Soft’ landscaping during cooler Autumn months

Contact us

To find out more about this project and other activities, please contact:

 [email protected]

 131 722

Please note this inbox is monitored Monday to Friday, 9am to 5pm.

Last updated: