FAQs

The study objectives were to update the hydrologic and hydraulic modelling for the Wianamatta South Creek catchment for floods up to the Probable Maximum Flood.

• Hydrological modelling analyses rainfall and calculates the catchment runoff.
• Hydraulic modelling analyses depths and flow rates in rivers or creeks, or in overland flow.

The information presented in the study will form the basis for the future Floodplain risk management study and plan for the catchment. This will assess the impact of flooding on existing and future development and present a plan of works for managing flood risk across the Wianamatta South Creek catchment within Blacktown City.

Your property has a higher risk of being affected by flooding from Wianamatta South Creek than other properties in our City.

The Wianamatta South Creek flood study has updated the 'flood planning level' in the Wianamatta South Creek catchment. The flood planning level is a combination of flood levels determined by the flood study and freeboard. Land below the flood planning level is located within the flood planning area.

We are required to inform our community of we have flooding information about a particular property. One of the ways we inform our community is through notations on a Section 10.7 planning certificate. These are specific to each individual property and contain information such as planning controls and other property constraints, like land contamination, bushfire risk and flood risk.

To show flood risk for a property, planning certificates must indicate if the land or part of the land is within the flood planning area and subject to flood related development controls.

The study is not expected to impact the cost of your insurance, though the cost of insurance premiums may increase for other reasons.

In partnership with state and territory governments, the general insurance industry has developed and licensed the National Flood Information Database (NFID) for use by insurers in determining the flood risk for individual properties.

Most insurers use this database to determine the flood risk to individual properties, and calculate the premium based on this risk and other criteria including building type, location and claims history.

House prices vary continuously with changes in the real estate market and are based on a large range of criteria including, but not limited to, location, size and age, which are not under the control of Council. The impact of flood development controls also varies greatly from one property to another, so a Section 10.7 planning certificate notation may or may not affect your property value.

The study is currently on exhibition until 8 March. An assessment of submissions received from this process will be reported to Council, which will then decide whether to adopt the study. If the study is adopted:

• we will update our maps and databases to reflect the most recent flooding information
• we will prepare a Floodplain risk management study and plan for Wianamatta South Creek, subject to funding being available.

The Floodplain risk management study will evaluate management options for the floodplain in respect of both existing and proposed development. This will include the assessment of various:

• flood modification measures such as levees, pipe upgrades and channel improvements
• property modification measures such as the development of a set of flood related development controls that would apply to future development located on flood prone land
• response modification measures such as improvements to flood emergency planning and weather warning systems.

The Floodplain risk management plan will set out a preferred set of measures aimed at managing the flood risk in the Wianamatta South Creek floodplain. Once adopted, we will be able to seek funding from the NSW Government for its implementation.

To understand any proposed change in the classification of your property, you can visit our website or view the Wianamatta South Creek flood study online here.

We comply with the NSW Government's Flood Prone Land Policy and Flood Risk Management Manual (2023). The process involves collecting flood data, creating a flood model and flood maps to understand the flood risk in the catchment.

We have used up-to-date modelling techniques, as well as expert assistance from consultants and the NSW Government, to determine mapping and analysis of risk. We believe our flood level estimates are as accurate as possible at this point in time. The Wianamatta South Creek flood study has also been peer reviewed to ensure it accurately reflects the views of multiple experienced professionals.

Our website provides answers to further questions on flood levels, insurance, planning certificates and development. Additional information can also be found on the following websites:

• NSW State Emergency Service https://www.ses.nsw.gov.au/plan-and-prepare/flood
• Bureau of Meteorology https://www.bom.gov.au/resources/learn-and-explore/flood-knowledge-centre