Flood Studies and Floodplain Risk Management Studies

Council engaged WMA Water to complete the Bayside West Floodplain Risk Management Study and Plan, which was adopted by Council in 2023. The Floodplain Risk Management Study and Plan updated the flood study data for each of the sub-catchments in the study area to capture changes which had occurred since the flood studies were completed. This may have included the construction of new buildings and other development. It also updated the models, so they were consistent with the latest guidance material (Australian Rainfall and Runoff, 2016).

Bayside West Floodplain Risk Management Study and Plan Part 1
Bayside West Floodplain Risk Management Study and Plan Part 2
Bayside West Floodplain Risk Management Study and Plan Part 3
Bayside West Floodplain Risk Management Study and Plan Part 4
Bayside West Floodplain Risk Management Study and Plan Part 5

Each of the Bayside West sub-catchments and a short summary of the areas can be found below. The flood study reports can be downloaded from this page, but have been superseded by the updates completed as part of the Bayside West study.

Bardwell Creek and Wolli Creek Catchment

Bardwell Creek is a tributary of Wolli Creek. Wolli Creek is in turn a tributary of the Cooks River with its confluence at the Tempe railway bridge crossing the Cooks River.

The study area contains the portion of Bardwell Creek and Wolli Creek within Bayside Council LGA and covers an area of approximately 713 hectares (7.1 km2). The upper catchment includes parts of Hurstville, Penshurst, Beverly Hills and Narwee within the Georges River LGA. The northern side of Wolli Creek includes parts of the suburbs of Roselands and Earlwood within the Canterbury Bankstown LGA.

Bardwell Creek Flood Study Volume 1
Bardwell Creek Flood Study Volume 2 

Bonnie Doon Catchment

The Bonnie Doon catchment is a minor sub-catchment of the Cooks River, having a total catchment area of approximately 2.7km2.

The catchment is heavily urbanised with medium density residential developments in the upper catchment, and higher density residential, light industrial and commercial developments in the lower reaches downstream of Bonar Street. The study area also includes the Eve Street Wetlands. The main discharge to the Cooks River is via the Bonnie Doon Channel through Cahill Park. A flood study for this catchment was completed by BMT WBM in 2017.

Flood Study

Sans Souci Catchment

The Sans Souci catchment is 3.1km2 and is bound by Botany Bay in the east and Rocky Point Road in the west. Ramsgate Road borders the catchment in the north and includes the uppermost part of the Scarborough Ponds. The catchment is drained by Waradiel Creek, Bado-Berong Creek and Goomun Creek that all flow into Botany Bay.

Land use within the catchment is dominated by low and medium density residential properties with commercial areas along Rocky Point Road and Russell Avenue. Several parks and reserves are located within the catchment and are mostly located along to the three creeks. 

A flood study of the catchment was completed in 2015 by Cardno and subsequently supported by the NSW and Commonwealth Governments with funding under the Natural Disaster Resilience Programme. 

Volume 1 Flood Study
Volume 2 Flood Study

Spring Street, Muddy Creek and Scarborough Ponds Catchments

This catchment study area of 13.1 km2 includes three catchments, Spring Street Drain and Muddy Creek that discharge to the Cooks River and Scarborough Ponds that discharges directly to Botany Bay.
The catchment study area is bounded by the Cooks River to the north, Forest Road to the west and Ramsgate Road to the south.  

The land use within the catchment is primarily medium to high-density housing with some commercial developments. The catchment also includes some large open spaces Barton Park, McCarthy Reserve, Gardiner Park and various reserves along Scarborough Ponds. BMT WBM completed the flood study for this catchment in 2017.

Volume 1 Flood Study
Volume 2 Flood Study

Council currently has floodplain risk management studies and plans completed for each of the catchment areas comprising Bayside East. This is excluding the small area of the LGA which sits within Birds Gully and Bunnerong Road Catchment, which is currently being completed by Randwick Council and a draft report is expected to be available for public exhibition in 2024. 

Council is planning to undertake a review of each of the flood studies completed within the Bayside East area and update them to ensure they represent current land uses, infrastructure and that they comply with relevant standards and guidance material. 

Each of the Bayside East sub-catchments and a short summary of the areas can be found below. The flood studies and floodplain risk management studies and plans can be downloaded from the links provided. 

Birds Gully and Bunnerong Road Catchment

The study area encompasses the Bayside suburbs of Daceyville and Hillsdale and part of Eastgardens.

The majority of the watercourses within the catchment have been replaced with trunk drainage that drain to the Botany Wetlands within the Eastlakes Golf Course. The Bunnerong Road catchment discharges to both Botany Bay and Lurline Bay, located within the Randwick LGA.

Bayside Council and Randwick City Council jointly completed the flood study for this catchment in 2018. The study was supported by the NSW and Commonwealth Governments and adopted by Bayside Council in August 2020. The Floodplain Risk Management Study and Plan is currently being completed, and is expected to be available for public exhibition in 2024. 

Flood study report volume 1 
Flood study report volume 2 

Botany Bay and Foreshore Beach Catchment

The Botany Bay and Foreshore Beach catchment is approximately 3.5km2. The eastern side of the catchment drains to Sir Joseph Banks Park and the western side drains to the Mill Stream, before discharging to Botany Bay. The topography of the catchment is generally flat with the exception of a low ridge along the eastern boundary. Development in the catchment is comprised of high density residential, commercial and industrial buildings.

Flooding in the catchment occurs as a result of runoff, during rainfall events, pooling in low lying areas due to a constrained stormwater system. The slow drainage is exacerbated when high tides or storm surges in Botany Bay, coincide with rainfall events. The general flatness of the catchment also means that some areas of the catchment are susceptible to tidal inundation even during dry weather. This areas are at higher risk during spring tides, storm surges and from future sea level rise.

BMT WBM has completed the Botany Bay Foreshore Beach Flood Study for this catchment in 2015 to analyse the risk of flooding.

Botany Bay Foreshore Beach flood study

Council engaged Jacobs Pty Ltd to undertake a Floodplain Risk Management Study in 2018 to investigate how Council can reduce the flood risk. The study was supported by the NSW and Commonwealth Government with funding under the Natural Disaster Resilience Programme.

Botany Bay Foreshore Beach Floodplain Risk Management Study - Part A
Botany Bay Foreshore Beach Floodplain Risk Management Study - Part B
Botany Bay Foreshore Beach Floodplain Risk Management Study - Part C

Mascot, Rosebery and Eastlakes Catchment

The suburb of Mascot is divided by the SWSOOS (ocean outfall sewer) and bounded on the west by the Alexandra Canal. The eastern side generally falls to the south eventually draining via the piped network to Botany Bay or via absorption into the Botany Aquifer. The freight rail line to the south forms a major hydraulic feature of the catchment obstructing overland flow to the south.

Botany wetlands is the largest coastal freshwater wetland system in the Sydney region. The wetlands and ponds cover an area of approximately 58 ha. These wetlands provide a major recharge source for the Botany Sands Aquifer.

A Flood Study for this catchment was completed by WMAWATER in 2015.

Mascot, Rosebery and Eastlakes Flood Study Vol 1
Mascot, Rosebery and Eastlakes Flood Study Vol 2

Royal Haskoning DHV completed the Floodplain Risk Management Study and Plan (FRMSP) of the Mascot, Rosebery and Eastlakes catchment in 2018. This study adopted by Council in 2019.

Mascot, Rosbery and Eastlakes Flood Risk Management Study and Plan

Springvale Drain and Floodvale Drain Catchment

The Springvale Drain and Floodvale Drain catchment encompasses an area of approximately 3.75km2 includes the suburbs of Pagewood, Eastgardens, Botany and Banksmeadow.

The catchment is heavily urbanised and is predominantly comprised of industrial development with a large proportion of residential development in the upper catchment.

The natural drainage systems have been heavily modified and most of the study area is now drained by a stormwater pipe network; there are some open channel reaches in the southern area of the catchment. When the capacity of this stormwater drainage network is exceeded, overland flow will occur along the alignment of the original drains or gullies.

A flood study for this catchment was completed by BMT WBM in 2014.

Springvale Drain and Floodvale Drain Flood Study
Springvale Drain and Floodvale Drain Appendix A 1-18
Springvale Drain and Floodvale Drain Appendix A 19-34
Springvale Drain and Floodvale Drain Appendix B  

A Floodplain Risk Management Study was completed in 2017 by WMAWATER. 

Springvale Drain Floodvale Drain Floodplain Risk Management Study and Plan Part 1

Springvale Drain Floodvale Drain Floodplain Risk Management Study and Plan Part 1