Ballina Shire council in the flood-ravaged Northern Rivers region of New South Wales is embarking on a community based project to share descriptions and photos of observed overland flooding, as part of its drive to improve flood resilience.
The aim is to include this information as part of better understanding flooding, its impacts and ways to better mitigate the risks into the future.
The Council has some existing modelling based on past events which is used as part of the existing 10.7 Certificate and will include detailed accounts of the March 2022 flooding. These will form part of ongoing Stormwater Drainage Management Studies and a Stormwater Masterplan. Existing areas include Ballina Island, West Ballina, Alstonville, Wardell and Lennox Head. The projects are funded by Ballina Shire Council in partnership with the NSW Department of Climate Change, Energy, the Environment and Water (DCCEEW).
Surface or overland flooding occurs when heavy rain flows over the ground, typically as local drainage systems can’t deal with the volume of water. Given the amount of hard standing and concrete these can occur in streets or yards and water then pool in low lying areas.
The studies can then form options for improving stormwater drain capacity and upgrade projects that could improve drainage. It will also support town planning, future development approvals and emergency response planning.
An online survey is open to the public from 20 November to 20 December 2024. Community members can find more information on these projects, complete the survey and share information via the Council YourSay page at www.yoursayballina.com.au/overland-flood-study.
The interesting takeaway here is that Councils are taking this on themselves in a piecemeal fashion, built on past events and individual records. The method for a similar Council facing the same risk may be entirely different and deliver other recommendations. And this is at the heart of Council derived and informal data – it focuses on the local area and it doesn’t take account of future risk modelling.
Knowing what has happened is fine, but you need to model what could happen over the next 30 years. Here at Groundsure, we have developed modelling for flooding, including overland, river and tidal flooding for 5 and 30 year time periods on a consistent basis for the whole of New South Wales. This approach can be used by Councils, homebuyers and homeowners alike to understand how flooding and other physical climate risks could impact on their communities, the value and insurability of their homes and facilities.
This consistent approach, built on the latest climate modelling, is more robust than the existing 10.7 for property transactions. Our ClimateIndex™ report is now being used by many conveyancers to alert clients to the risks, often identifying future risks that the 10.7 does not pick up.
We can also provide a property-level analysis to help Councils plan street by street on how they can develop their emergency and mitigation plans – not just for flooding, but in relation to bushfires and coastal erosion.
For more information on the ClimateIndex report and our data modelling, get in touch at info@groundsure.com.au or call us on 02 7912 0117.
References:
https://www.echo.net.au/2024/11/how-does-flooding-impact-you