Flooding can occur from several different sources. It is important to understand the various flooding sources so that an appropriate modelling methodology and design considerations can be identified. The various sources of flooding and their specific design considerations are presented below.
Due to significant flood events in the past, Brisbane City Council have engauged hydraulic engineers to undertake detailed hydraulic modelling of the Brisbane River. Flood levels for properties affected by flood water from the Brisbane River can be found in Floodwise Property Reports, which are available for free on Brisbane City Council's website. A link to the floodwise property reports search page can be found in the Links page of our website.
Creek/Waterway flooding can create significant deveopment constraints on a property. It must be demonstrated that developoment would not impact the hydraulic conveyance or flood storage of the Creek or Waterway. Development within a Creek/waterway is usualy required to be modelled using a 2-dimensional modelling package. Details of 2-dimensional modelling packages can be viewed in our Software page.
Other factors impacting development within a Creek/waterway flood area include the flow velocity, flood hazard, land use acceptability and freeboard requirements.
Overland flow is runoff that travels across the land after it rains, either before entering a waterway, after breaking out of a waterway, or rising from the ground. Overland flow usually occurs during or following short intense rainfall events. Development in overland flow paths must not create an adverse impact on neighbouring properties. Blocking an overland flow path would divert the overland flow onto a neighbouring property and likely cause an increase in inundation levels. If the overland flow cannot be diverted around the proposed development, it is likely that the development will have to be constructed on a suspended floor to allow overland flow to travel underneath the development.
Stormtide flooding is the inundation of dry land from a rise in sea levels or tidal event. Stormtide inundation usually occurs in severe weather events such as cyclones. Council's in South East Queensland have undertaken coastal flood modelling and provide storm tide flood levels.