Understanding flooding

Flooding occurs during extreme weather when normally dry land is inundated. Flooding is a natural phenomenon. There are three main types of flooding in Sutherland Shire:

  • Overland flooding: stormwater runoff flows overland towards a waterway.
  • Mainstream flooding: rising water levels in creeks and rivers overtop banks and inundate surrounding land.
  • Coastal flooding: inundation of low-lying coastal areas caused by a combination of high tides, storm surge and waves.

These types of flooding can occur in isolation or in combination.

A floodplain is an area of land inundated up to the probable maximum flood (PMF). The PMF is the largest flood that can occur. While it is difficult to prevent flooding, the risks can be managed.

Floodplain risk management

Like nearly all urban areas in Australia, Sutherland Shire has a history of flooding.

Council follows the NSW Government’s Flood Prone Land Policy as described in the 2023 Floodplain Development Manual, to manage flood risk.

Council’s floodplain management program has been in operation for many years. Studies are conducted to determine the extent of flooding and management actions are then assessed, recommended and implemented.

The flood risk across Sutherland Shire is illustrated on this map and is regularly updated.

Floodplain risk management is overseen by Council’s Floodplain Management Committee and includes representatives from Council, NSW Government and the community. The NSW Government provides technical and financial assistance to Council under the NSW Government’s Floodplain Management Program. Council is also supported by Floodplain Management Australia.

Find out if your property is prone to flooding with these tools:

  • Shire Maps: a flood-prone land map shows flood risk and planning area.
  • Flood studies and floodplain risk management studies and plans: see below detailed reports describing flood behaviour and flood risk.
  • Flood information sheets: contact us for flood information specific to an individual property.
  • Section 10.7 Certificate: identifies whether an individual property is affected by flood-related development controls.

Before requesting Flood Information, you should contact our Stormwater and Waterway Assets Unit on 9710 0333 to confirm flood information is available for your property. (Fees apply).

Flooding and your property FAQs

Submit an application for flood information

Preparing for and responding to flooding

All flood-affected property owners must be prepared for flooding. Find more information from NSW SES and Insurance Council of Australia.

You can also refer to our Disaster Dashboard.

Flood studies and floodplain risk management studies and plans

Council has completed numerous flood studies and floodplain risk management studies and plans over the decades. These are undertaken by specialist consultants using up-to-date data, flood modelling software and floodplain risk management practices.

The aim of a flood study is to help keep people and property in our community safe from the impact of severe, sudden rain, which causes ‘over land’ or flash flooding. During flash floods, stormwater drains fill quickly and the excess rainfall flows over land.

Contact us to request a copy of the flood studies.

Flood Studies in Progress

We have prepared a draft Overland Flow - Flood Study for the Sutherland Shire. Find out more about the Draft Overland Flow - Flood Study process and community updates.