Flood management

Floodplain mapping

Why do we do it?

One of the strategies identified in Water Futures, developed as part of our Community Plan in 2008, was to Manage Stormwater to Protect and Minimise Risk to Property Infrastructure and Public Health and Safety.

To help deliver this strategy we have undertaken studies to determine the possible high flow rates and anticipated flood flow paths of watercourses in our city.

We use this information to help inform our development plan, and identify potential stormwater infrastructure improvements.

Flood management - Nashwauk Cres
Nashwauk Crescent (Pedler Creek) Moana, 2005  

Improving our flood information

Over the past four years a number of these studies have been completed and we now have reliable flood information for all our major stormwater catchments.

The studies have a technical focus, so to help our community also understand about flood risk in our area we have produced information sheets. 

The information sheets summarize the study findings and show the flood extents for major floods in each of the catchments, along with information on how to read the flood maps, how we create the maps and the limitations of the maps. 

The information sheets are available by clicking on the study name, or by calling our customer service centre on 8384 0666.

If you aren’t sure if you are within one of these flood mapped areas, you can quickly check by looking at the flood map index, which shows the flood mapped extents on a map of the council area.

We have also developed a series of frequently asked questions (FAQs) to try and help answer any questions you may have about our floodplain mapping.

Note that the use of our flood plain maps should acknowledge these limitations.

Technical information on the process we use to develop the maps, and an explanation of technical terms is available here.

If you have any questions and cant find the answer to the question you have in our of frequently asked questions (FAQs)  or the information sheets, please contact our customer service centre on 8384 0666, or email your query to mail@onkaparinga.sa.gov.au

What does it all mean?

Fortunately, as our city has developed, open space has been provided along many of our major watercourses.  As a result, less than 2% of all residential properties in the Council area are identified as “flood prone”. (Note – even if only a small part of a property has shallow floodwaters, we still call it “flood prone”).

As a result of the completion of these studies we will look at ways to minimise risk and hazard associated with the identified flood extents. 

There are many options available for reducing the impact from floods, including:

  • placing controls on development in high flood risk areas, (our development plan now identifies flood prone land)
  • providing flood warning systems where sufficient advance warning notice can be provided to assist with orderly evacuation or preparation,
  • building flood mitigation structures where feasible, and
  • improving community awareness and resilience to ensure the community is prepared and able to respond.

Be prepared

Although our flood mapping helps identify higher risk areas, each flood event is unique.  The severity of flooding in a single event cannot be reliably predicted.

It is possible that localised flash flooding can occur from heavy rain within or outside of the mapped catchments, or floods may be greater, or behave differently from the events we have modelled. 

For these reasons, it is a good idea to be prepared – especially if your property is within the flood mapped areas, but even if it isn’t!

One of the simplest things that can be done to reduce loss or damage from flooding, is to make sure you have your own personal, household emergency flood plan.  To help you develop one of these, we have prepared this guide

We have also engaged with the State Emergency Service (SES) to deliver their Floodsafe and Stormsafe program in schools and the community throughout the area, to help build community resilience and understanding about flood risk.

The Bureau of Meteorology provides a severe weather warning for potential for flash floods, and floods on most watercourses in our council area, as well as a flood warning service for the Sturt River and Onkaparinga River.  Current information on rainfall and river levels is available on the BOM flood Adelaide rainfall and river conditions page.

In the event of a flood emergency the State Emergency Service (SES) –telephone 132500, is the response authority.

More information about the SES and the Floodsafe and Stormsafe program can be found on the SES website