Brisbane Water Foreshore Flood Study

The main objective of this study (in two parts) has been to determine water levels in Brisbane Water for\r\nthe full range of flood and ocean events that can occur due to the various natural physical\r\nprocesses, taking joint occurrence issues into account to some extent. The flooding\r\nbehaviour can be influenced, either separately, or by a combination of, catchment rainfall\r\nrunoff flooding, rainfall directly onto Brisbane Water, elevated ocean levels, local winds\r\nand, to a minor extent, the condition of the ocean entrance channel near Ettalong.\r\n\r\nThe outcomes from this study include: -\r\n\r\n* Public Participation: Community consultation is highly important in the whole process\r\nleading to the development of a sustainable floodplain risk management plan and is an\r\nessential component of the flood study. An information leaflet and questionnaire were\r\nprepared and delivered to residents, whose properties were considered to be lower than\r\n2.5m AHD (see Figure 4.2) and potentially at risk of inundation.\r\n* Brisbane Water Design Foreshore Flood Levels: This Study has determined design still\r\nwater levels and flood extents for a full range of flood events for existing catchment\r\nconditions. All contributing physical processes of wind, rain, waves and tide were\r\nconsidered. Cardno Lawson Treloar, as part of the Brisbane Water Estuary Processes\r\nStudy, have set up and calibrated hydrologic and hydrodynamic models of the catchment\r\nand waterway, respectively, as well as fine grid wave models of sub-regions of the\r\nwaterway. This calibration process involved some months of work and hence having these\r\nmodels ‘ready-to-go’ helped the study schedule.\r\n* Hydraulic and Hazard Categorisation: To achieve effective and responsible floodplain\r\nrisk management, the Brisbane Water floodplain was divided into areas that reflect the\r\ndifferent hydraulic impacts of development activity on flood behaviour and the hazard\r\nimpact of flooding on development and people.\r\n* Floodplain Risk Management Measures: This study forms the basis for a future Brisbane\r\nWater Foreshore Flood Risk Management Study and Plan, where detailed assessment of\r\nflooding risk management measures and a damages assessment will be undertaken for all\r\nurban settlements along the foreshore of Brisbane Water. Cardno Lawson Treloar have\r\nundertaken many Floodplain Risk Management Plans and undertook this study keeping\r\nthose future needs in mind.