Why is the Floodplain Risk Management Study and Plan being reviewed?

    We make computer models and maps that show where it could flood and by how much. From time to time, these models are reviewed and predicted levels may change. The reasons why can include:

    • New floods occur, providing additional data to fine-tune the model.
    • More advanced computer models or methods for estimating flood levels become available.
    • Changes in the catchment, such as flood mitigation works or new developments.
    • Changes in policy.

    After we update flood models, we also need to update our understanding of what the risks/damages from floods might be. We then need to update our plan for mitigating (reducing) these. This is what a floodplain risk management study and plan does. It has a prioritised plan of recommended measures to best address existing and future flood problems in the catchment. It also includes guidelines for all future developments in the area. 

    What are the recommended measures for the Mullet Creek Catchment?

    Debris control structures for Unara Road and Princes Highway (FM1 on map)
    Flooding occurs at Princes Highway and Unara Road during large storms. There is a big risk this flooding would be worsened if the culvert (tunnel or drain structure) was blocked.

    Unara Rd and Princes Hwy culverts:


    We’re considering building debris control structures near these culverts to stop debris getting in and preventing this potential blockage.

    An example of a debris control structure:

    Levee Options
     There are locations where levees would be considered to provide protection to properties during floods in Mullet Creek. These are shown near Prince Edward Drive (FM2), Kembla Grange Industrial Estate (FM9) and Essex Street (FM8). The primary aim of the levees is to hold back floodwater from areas impacted. Levees provide protection to properties and infrastructure. However, they:

    • Require ongoing maintenance once installed.
    • Can have a very high cost.
    • Look similar to the example shown in the picture, but can also be higher or lower, and 
    • Provide a false sense of safety from floods. They can still overtop in extreme floods.

    An example of a levee:

    Creek Maintenance (FM6)
    Natural vegetation is important because it provides habitat, shelter and protects against erosion. However, weeds and debris can affect flood flows. This can have impacts on our use of the land and public safety. We currently do some selective vegetation management across the Mullet Creek area, in locations that will reduce the impact of flooding. The proposal is to consider additional areas that would allow us to better manage our flood risk.

    Taywood Park basin upgrade and blockage control (FM4)

    A proposed option is to upgrade Taywood Park’s existing detention basin to have a larger volume. A detention basin is a holding pond that temporarily stores some of the stormwater run-off from a catchment during big storms. A proposed debris control structure and safety fence would also be installed. This would prevent blockage of the outlet and reduce the risk of people being pulled into the drain during floods.

    Enhanced Storage Areas (ESAs) (FD2)
     ESAs work in a similar way to detention basins. They are located within the floodplain in areas where floodwater fills the area upstream of a narrowing in the landscape, e.g. a gully. This provides an opportunity to provide temporary floodwater storage on the floodplain and release the flood flows at a slower rate. The ESAs do not alter the flows in smaller floods, but do limit flows when the event is larger and less frequent. 

    Small levee at Ena Avenue (FM3)
    A small levee is being considered for the south-western end of Ena Avenue to stop floodwater from Mullet Creek affecting properties. This levee would be small in size. This will require some earthworks in the location shown on the map:

    Other options
    Other options recommended to help manage flood risk in this catchment include:

    • Improving flood warnings.
    • Controls to make sure new developments don’t increase flood impacts. 
    • Improving emergency management. 

    Where can I get information about flood levels on my property?

    We have historical flood level records and/or our completed flood studies for some properties, but not all. Please contact our Customer Service team on (02) 4227 7111 to find out what’s available for your property.

    What happens next?

    After we’ve completed the Floodplain Risk Management Study and Plan, more work will be done to develop concepts and detailed designs for the recommended stormwater structures. We’ll take these out to the community to seek further input before the designs are completed.

    How will my feedback be used?

    At the end of the engagement period, we read and consider all feedback. We write a report about the engagement and what we heard. It is provided to the project team and Southern Floodplain Committee for consideration in making a decision.

    How can I join the conversation?

    • Online  www.our.wollongong.nsw.gov.au                           
    • Email    engagement@wollongong.nsw.gov.au                                
    • Write    Locked Bag 8821, Wollongong DC 2500                
    • Phone   (02) 4227 7111                                      
    • Drop-in Information Session (no presentation)
      When: Thursday 13 October 2022 - drop in anytime between 3:30-6:30pm
      Where: Dapto Ribbonwood Centre (Kurrajong 2 room) -  93/109 Princes Highway, Dapto    

    If you’re d/Deaf or have a hearing or speech impairment, you can contact us through the National Relay Service. If you need an interpreter, you can contact us through the Translating and Interpreting Service on 131450. You’ll need to provide our phone number 02 4227 7111 for either service.