Floodplain Management

Stormwater is generally managed by Council's stormwater drainage system of pits and pipes. However, the capacity of the drainage system is sometimes exceeded, causing flooding. Flooding is defined in several different ways:

• Overland flooding: Intense rainfall can create excess runoff which flows overland once the capacity of the drainage system is exceeded.
• Tidal/oceanic flooding: Due to their low elevation, some areas of Bayside are susceptible to inundation caused by very high astronomical tides (i.e. king tides) or elevated oceanic level events (e.g. storm surge). The elevated tide and ocean levels cause water to back up existing trunk drainage pipes and flood low lying areas in the catchment.
• Mainstream flooding: Intense rainfall can overflow the natural banks a creek, lake or river and flood areas adjacent to the waterways.
• Major flooding can be caused when mainstream flooding, overland flooding and tidal/oceanic inundation events coincide.

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Council develops and implements Floodplain Risk Management Plans which provide a range of measures to reduce the impact of flooding. This work is guided by the Floodplain Risk Management Manual (2023). Creating a Floodplain Risk Management Plan involves a number of stages.

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The objective of the Flood Study is to identify the nature and extent of flooding within a catchment. Being aware of the flooding potential in a catchment and identified responses, reduces the risk to life and property during flood events.

The objective of Floodplain Risk Management Plans is to identify the existing flood environment and recommend specific measures to manage the impact of flooding. Flood behaviour, evacuation issues and site access are all taken into consideration.

During the implementation phase, Council progressively prepares Flood Studies, Floodplain Risk Management Studies and Plans for each catchment.

Following planning, actions are put in place. Key actions include:

• Setting planning rules to reduce the impact of flooding from and on new developments.
• Building, upgrading and maintaining stormwater structures including channels, detention basins and debris control structures to reduce the risk of blockage and floods.
• Purchasing eligible properties that have a high flood risk under a voluntary purchase scheme.
• Providing flood information to the community so informed decisions about buying or developing land can be made.
• Maintaining waterways managed by Council and encouraging other land owners to maintain their waterways.
• Planning how to respond to and recover from floods.

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Community consultation is an integral component of every stage of the Floodplain Risk Management Plan process. At key stages, residents are invited to provide feedback about flooding issues and potential flood management measures. Our Floodplain Risk Management Committee also includes community representation. Learn more about the Floodplain Risk Management Committee.

The Bayside Council area has 10 catchment areas, across the west and east sides of the LGA:

Bayside West

1. Bardwell Creek and Wolli Creek Catchment: Turrella, Bardwell Valley and Bardwell Park, Bexley North, Kingsgrove
2. Bonnie Doon Catchment: Arncliffe, Wolli Creek, Bonar Street
3. Sans Souci Catchment: Ramsgate, San Souci, Monterey, Kogarah (part)
4. Spring Street, Muddy Creek and Scarborough Ponds Catchments: Banksia, Rockdale, Carlton, Bexley, Kogarah (part), Brighton Le Sands, Kyeemagh

Bayside East

1. Birds Gully and Bunnerong Road Catchment: Daceyville, Eastgardens, Hillsdale
2. Botany Bay and Foreshore Beach Catchment: Botany and Port Botany
3. Mascot, Rosebery and Eastlakes Catchment: Mascot, Rosebery and Eastlakes. The study also includes the Botany Wetlands catchment.
4. Springvale drain and Floodvale drain Catchment: Banksmeadow and Pagewood (part)

Minor catchments with minimal housing:

1. Botany Bay Catchment: Coastal strip impacted by storm surges and ocean dominant flooding.
2. Botany Wetlands Catchment: Flood modelling has been completed for the Mascot, Rosebery and Eastlakes Catchments.

Find out more about the catchments and latest actions here.

The following projects are currently being completed by Council:

1. Feasibility study and concept design of floodplain risk management options in the Botany Bay Foreshore Beach catchment. This project is assessing the feasibility of flood mitigation works in William Street, Botany and Dent Street, Banksmeadow and will be completed by the end of 2024. This project is funded by the NSW Government’s Floodplain Management Program. 
2. Detailed design of flood mitigation works in Baxter Road and Hollingshed Street. This project is designing pipe upgrades in both areas 

Do you live in an area at risk of flooding? Flood extent map, hazard layers and flood affected property information are available in Council’s online mapping system. The NSW State Emergency Service has information that can help you before, during and after a flood.

Prepare Your Home and Business

Be Aware