Flood - Levels 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: 1% Chance of Flooding in Any One Year
<i>Likelihood: PossibleAnnual Exceedance Probability (AEP): </i><i>1%</i>
<i>Average Recurrence Interval (ARI): 100 Year</i>
A large uncommon flood event that is rarely observed but nevertheless still possible. Over a long period of time an event of similar size may occur on average once every 100 years. It is therefore likely an event of this size will occur at least once during a single lifetime. It is less likely, but still possible, for a flood of this size to occur more than once in a single lifetime. A flood event of similar size occurred in the middle and upper reaches of the Caboolture River during January 2011.
<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