Floodplain management

Floodplain management

Managing floods in the local area

Floodplain management plans for the City of Sydney local area have been developed and adopted by Council. The plans include flood mitigation measures and what can be done to help affected areas.

Under the NSW Government's flood prone land policy the City is required to manage flooding issues and put plans into place to safeguard flood-prone areas.

The local area has been divided into 8 catchments covering 2,666ha.

You can also click an area of the map below to show further information for each catchment.

Due to high urbanisation since the 19th century across the local area there are not many natural creeks or open surface water bodies in the catchment areas to accommodate stormwater.

Generally, stormwater from frequent minor storm events is managed by conventional pits and pipe systems. In less frequent, but major rainfall events, stormwater in excess of the conventional systems travels along low gradients of the catchments, ultimately draining into Sydney Harbour and Botany Bay.

The combination of steep and flat terrain, high density residential, commercial and industrial areas has made areas susceptible to flash flooding. Being aware of the potential for flooding and knowing how to respond will make flood events more manageable.

We are progressively introducing the floodplain management plans, in the final stage of the floodplain risk management process, as outlined in the NSW Government's flood prone land policy.

Alexandra Canal catchment Centennial Park catchment Rushcutters Bay catchment Woolloomooloo catchment Sydney City catchment Darling Harbour catchment Blackwattle Bay catchmen Johnstons Creek catchment

Floodplain risk management measures

There are 35 structural and 14 non-structural flood mitigation measures across the local area that were recommended in the relevant floodplain management plans. The priority ranges from low to high for implementing the mitigation measures over the short to long-term period.

In 2016, the total estimated cost to undertake the recommended mitigation works in the local area is $363m. The works will require collaboration between the City and state government agencies such as Sydney Water and NSW State Emergency Services.

We are now undertaking the following works with Sydney Water:

Interim floodplain management policy

Council endorsed its draft interim floodplain management policy in May 2014.

The policy is a responsible and forward-thinking approach to manage flooding issues, which will ensure development in the city is not at undue risk of flood and that proposals do not increase flood risk for existing properties.

Flood models 

We have an extensive suite of flood models that were developed to prepare the flood studies. 

You can make a formal request to access the flood models for a small fee and subject to a data sharing agreement.


NSW Government: Floodplain Development ManualNSW State Emergency Service FloodSafeBureau of Meteorology: NSW weather and warnings summary

Local flooding history

Since 1910, the City of Sydney's local area has experienced 35 floods classified as serious, severe or minor. In 13 cases, high rainfall resulted in localised flooding. During this period 4 floods were classified extreme in November 1984, March 1975, January 1973 and August 1971.

Floods can occur at any time and in the future could be bigger than any previously recorded event. 

Past flood events

Average time between floods of this size
January 1938
10–20 years
September 1943
20 years
June 1949
5 years
January 1955
5–10 years
November 1961
10–20 years
August 1971
20–50 years
January 1973
20–50 years
February 1973
10 years
March 1975
Greater than 1 in 100 years
November 1984
Greater than 1 in 200 years
January 1991
5–20 years
April 1998
10 years
February 2001
1 year

High rainfall storm events

Note: Rainfall levels recorded at Centennial Park, Randwick Bowling Club and Randwick Racecourse since 1888, which caused minor flooding throughout the city. 

Rainfall (mm)
January 1933
February 1956
February 1958
February 1959
November 1961
May 1962
March 1975
August 1975
October 1975
March 1978
November 1984
April 1988
February 1992

Last updated: Wednesday, 15 November 2017