Allans Creek Catchment

Council completed the Allans Creek Floodplain Risk Management Study and Plan in August 2024 for this catchment. The study was jointly funded by Council and NSW Government, and was prepared in accordance with the NSW Government’s Flood Risk Management Manual (2023) and the Australian Rainfall and Runoff 2019 guidelines.

The study provides the most up to date information on flooding for this catchment. The study also identified flood risk across the catchment, investigated various options and recommended a range of flood mitigation measures.

The Allans Creek Floodplain Risk Management Study and Plan dated August 2024 includes updated version of the Flood Study (2019) with ARR19 guidelines. The study also supersedes the 2008 Floodplain Risk Management Study and Plan.

The current Floodplain Risk Management Study and Plan (2024) including reports and model results are available for download from the NSW SES Flood Data Portal using the link below.

Allans Creek Flood Study & Floodplain Risk Management Study and Plan 2024 - Flood Projects - NSW Flood Data Portal

Planning matrix

We’ve added a matrix for the Allans Creek Catchment into Chapter E13 of the Wollongong Development Control Plan PDF PDF, 1824.81 KB. This helps people understand flood risks when they’re planning new development in the area.

F6 Median Strip

In 2005, NSW Roads and Maritime Services (now called Transport for NSW) removed a large median strip on the M1 Motorway at Figtree to allow flood water to pass over the road and reduce flooding upstream.

Options for Upper Byarong Creek

We’ve looked into several options to reduce flood impacts in the upper Byarong Creek area within Allans Creek catchment. These include:

• Installing a debris control structure upstream of Koloona Avenue.
• Creek works upstream of Koloona Avenue
• Changing the contour of the creek upstream of Koloona Avenue to create a detention area
• Adding a ring levee near the Casuarina Place and the Whelan Avenue / Coronata  Drive intersection in Figtree.
• Creating flood storage areas both upstream and downstream of Koloona Avenue. To do this, we would need to buy and clear some properties in the area.
• Creating a flood storage area near Casuarina Place and Eureka Street.

Of all the above options investigated, the installation of a debris control structure upstream of Koloona Avenue was ranked the highest. It was recommended that this proceed to detailed design.

Koloona Avenue, Figtree debris control structure - detailed design

We looked into installing a debris control structure upstream of Koloona Avenue (on the western side) to help reduce blockages. The cost outweighed the benefits so work is not going ahead.

However, we may investigate installing a debris control structure immediately upstream of the Koloona Avenue culverts. To do this we would need to purchase some key properties nearby. We’ll provide an update if this work becomes possible.

Options for Brandy and Water Creek

We investigated options to reduce flood risks near Darragh Drive, Figtree. This included lowering the west bank of the creek and associated works. However the cost of this work would outweigh the benefits, so it’s not going ahead.

Allans Creek debris control structures

We’ve prepared a concept design for two debris control structures upstream of the Princes Highway Bridge on American Creek, and upstream of The Avenue on Byarong Creek.

During the preliminary detailed design stage, it was found that construction of a debris control structure upstream of Princes Highway on American Creek is not viable. As a result, we are only proceeding to detailed design for the debris control structure upstream of the Avenue on Byarong Creek. A construction date is yet to be confirmed.

Princes Highway Bridge, Byarong Creek

We planned to improve the flow of water towards the Princes Highway Bridge, and reduce overflow to Arrow Avenue, Figtree.  Further investigation found that this option would have little benefit in reducing the flood levels in this area, so it’s not going ahead.

Vegetation management

We’ve been working since 2012 to manage plants and weeds on the edges of creeks on Council land. This helps to reduce erosion and keep creeks flowing well.

Blackman Parade Channel Reconstruction

We’ve installed rock scour protection on the creek bed and repaired the existing rock bank to improve water flow and make maintaining the creek easier.

Voluntary Purchase

We’ve earmarked 17 properties in this catchment for voluntary purchase. 11 properties have been purchased and cleared with funding support from the NSW and Australian governments.

You can help our research and planning for floods in this catchment by sharing your past experiences.

If you have photos or other information about flooding on your property, please contact us.

You can view the current Allans Creek Floodplain Risk Management Study and Plan and other older documents for this catchment on the NSW Flood Data Portal.

Current Documents

Allans Creek Flood Study & Floodplain Risk Management Study and Plan 2024