Flood Hazard Information
New flood mapping and analysis has been released to support the roll out of the Resilient Homes Program.
The new flood mapping and analysis indicates specific areas across the Northern Rivers which pose the greatest risk to life in most floods and therefore will be the first priority for buybacks.
About the flood mapping
The priority maps have been prepared based on the results of flood computer modelling information to identify areas that have different flood risk profiles.
These maps show four different colours that represent a scale of 1 – 4 using all the available information to map risk.
They also show the known floodplain extent (the white outline where shown).
The darker maroon colour being areas identified to be at the highest risk (identified as Priority 1), whilst other colours show areas that identified to be a risk identified as Priorities 2, 3 and 4.
Risk relates to the chance of the flood happening (probability) and the potential effect (consequence) of that flood.
The probability part of risk comes from consideration of what is known as a ‘design flood event’.
For the maps prepared, this came from information for the 1 in 20 chance of occurrence (annually), the 1 in 100 chance and the 1 in 500 chance flood event.
The consequence part of risk draws information about the depth and velocity of flooding (the combination of which is referred to as flood hazard) that is calculated using computer modelling for each design flood event.
The flood hazard analysis has been defined in accordance with the Australian Institute for Disaster Resilience Guideline. More information can be found via the Australian Institute for Disaster Resilience (AIDR).
How the maps will be used
This is the region’s most comprehensive flood mapping and analysis available – showing the relative risk to life for each neighbourhood and the order in which further Home Buyback, Home Raising and Home Retrofit offers will be prioritised.
The method for determining the location of prioritised homes includes where the risk to life is greatest under most flood scenarios and are likely to be inundated by high and fast floodwaters.
How to read the maps
Homes being prioritised under the Resilient Homes Program present the greatest risk to life to both residents and emergency response agencies sent to rescue them.
Priority 1 or Priority 2- Indicative Home Buyback Group A
Priority 3- Indicative Home Buyback Group B
Priority 4- Indicative suitable for Home Raising or Home Retrofit depending on the construction type of the home and if the floor level is lower than an estimated 1 in 20 chance per year flood level.
Outside priority areas 1 to 4- Not currently proceeding under the Resilient Homes Program.
The Reconstruction Authority is in the process of contacting homeowners registered for the Resilient Homes Program.
Tweed and Byron
Upper Clarence River