Moreton Bay City Flood Database
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.
Existing Conditions Maximum Scenario: 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.
Purpose: 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.
Methodology: 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. Refer technical
publications available from Council's website for further detail.
Flood Depth: Indicates the approximate
depth of potential inundation during a computer-modelled flood event (not
actual recorded levels). This dataset represents the raw modelled depth values
as a continuous grid of floating-point values.
Modelled Probability: The probability of
flooding represented by this dataset is: 0.1% Chance of Flooding in Any One Year
Likelihood: Unlikely
Annual Exceedance Probability (AEP): 0.1%
Average Recurrence Interval (ARI): 1,000 Year
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.
Version Notes 3.1.0 - 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)
Version Resolution: 2.5m
Data Reliability: A
Indicates the flood data is of the highest available
standard and has been prepared using the most recent flood model and input
data
Further Information: For additional
information on flooding in the Moreton Bay Region please see Council's
website: https://www.moretonbay.qld.gov.au/Services/Property-Ownership/Flooding
