Flood - Levels 0.1% AEP


<b>Moreton Bay City Flood Database</b>
River and Creek Flooding 
Version 3.1.0 (October 2023)



This theme shows river and creek flooding caused by long duration heavy rainfall, typically lasting between 1 hour and 1 day. Sometimes this rain falls over a whole catchment or a number of catchments. This extended period of heavy rainfall causes the water levels in the river or creek to rise and escape the main channel. It may take a number of hours or days for these floodwaters to rise, reach a peak and then subside. 

<i>Existing Conditions Maximum Scenario:</i> Maximum of modelled flood behaviour in rivers and creeks for different design rainfall events under existing climate and catchment conditions - with and without structure (bridges and culverts) blockage. 
<i>Purpose</i>: To determine flood levels and flows for different design rainfall events for design of infrastructure with and without bridges and culverts being blocked by debris. 
<i>Methodology:</i> Coupled hydrologic (WBNM) and hydraulic (TUFLOW) modelling using a two-dimensional regular grid, 1D culvert structures, 2D bridge structures and a design burst rainfall approach based on Australian Rainfall and Runoff 2019 guideline (ARR2019). Blockage calculated based on ARR2019 recommendations. <i>Refer technical publications available from Council's website for further detail.</i> 
<i>Flood Height:</i> Indicates the
approximate water surface level of potential inundation during a
computer-modelled flood event, expressed in meters above mean sea level. This dataset
represents the flood height values as contour lines using a contour interval of
0.2m.
<i>Modelled Probability:</i> The probability of flooding represented by this dataset is: 0.1% Chance of Flooding in Any One Year

<i>Likelihood: UnlikelyAnnual Exceedance Probability (AEP): 0.1%</i>

<i>Average Recurrence Interval (ARI): 1,000 Year</i>
A very large and very unlikely flood event. Over a very long period of time an event of similar size may occur on average once every 1,000 years.  Few people will ever witness an event of this size. When an event of this size is observed it is considered to be very exceptional. A river and creek flood event of similar size occurred in the middle reaches of the North Pine River during January 2011. Whilst very unlikely, it is possible for these events to occur.

<i>Version Notes 3.1.0</i> - First edition of Generation 3 models, incorporating 2019 LiDAR, ARR2019 for Hydrology and TUFLOW HPC for Hydraulic modelling. All ARIs and all aspects. (BCR 5yr, 10yr, 50yr and 2000yr runs completed by CMB). BYR and MAR no structure blockage only. MAR ARR hazard calculated using WaterRIDE. (October 2023)
<i>Version Resolution: 2.5m</i>
<i>Data Reliability: A </i>
<i>Indicates the flood data is of the highest available standard and has been prepared using the most recent flood model and input data </i>
<i>Further Information: </i>For additional information on flooding in the Moreton Bay Region please see Council's website: <a href="https://www.moretonbay.qld.gov.au/Services/Property-Ownership/Flooding">https://www.moretonbay.qld.gov.au/Services/Property-Ownership/Flooding</a>  

Tags: flood
Organization: City of Moreton Bay's Data Hub