Top Navigation

Floodplain Risk Management Study and Plan

Parramatta Road flooding 1990s

The former Leichhardt Council commissioned a Flood Risk Management Study and Plan to address

  • management of the hazards associated with flooding;
  • mitigation of the amount of flooding at or through properties

The Plan addresses flood management issues within the former Leichhardt Local Government Area (LGA) as identified in the Leichhardt Flood Study (Cardno 2010) (PDF 1.4MB).

flood doc timelineFlood hazard management and mitigation methods are broadly categorised into three categories – property modification (reducing the consequent of flooding through a property), emergency response (modifying the behaviour of people during a flood event to reduce the consequence of a flood risk) and flood modification measures (structural modification of flood behaviour to reduce the risk of flooding).

Preparation of the Leichhardt Flood Risk Management Study and Plan will include community consultation.

Consultants Cardno were commissioned by the former Leichhardt Council to undertake the Flood Risk Management Study and prepare the Flood Risk Management Plan.

Flood Risk Management Committee

At its meeting on 23 July 2013 Council resolved to establish the Advisory Leichhardt Floodplain Risk Management Committee (FRMC).

The purpose of the Committee is to assist Council in the preparation and implementation of the Flood Risk Management Plan. The Committee will provide the mechanism for formal engagement with the community. The Committee meets at key stages throughout the project.

The FRMC is made up of a balanced representation of stakeholders, such as agencies, groups and individuals affected by floodplain risk management or involved in its coordination.

State agencies and Councils were invited to join the Committee. Council also invited nominations from the local community and businesses, via advertising in the local paper in February/March 2014.

Committee members must be familiar with Council's Code of Meeting Practice and Code of Conduct.

The membership includes:

  • Councillors (Chair and two additional Councillors),
  • Council staff (engineering, urban planning),
  • Representatives of the local community,
  • Office of Environment and Heritage (OEH),
  • NSW State Emergency Services (SES),
  • Sydney Water,
  • Roads and Maritime Services (RMS),
  • NSW Fisheries,
  • Ashfield Council,
  • City of Sydney Council, and
  • Marrickville Council.

The most recent meeting of the FRMC was held on Wednesday 3 March 2016 at 2.30pm in the Leichhardt Town Hall.

A copy of the agenda can be found here:pdf-new-icon.gif Flood Risk Management Committee Agenda 3 March 2016 (PDF 1.8MB)
A copy of the minutes of the meeting can be found here: pdf-new-icon.gif Flood Risk Management Committee Minutes 3 March 2016 (PDF 140.1KB)

Following the proclamation of the Inner West Council in May 2016, the Advisory Leichhardt Floodplain Risk Management Committee was dissolved. The Inner West Council is currently working toward formation of a Floodplain Risk Management Committee for the new Council.

flood study area

The Study Area

The Leichhardt Floodplain Risk Management Study and Plan is being undertaken for the entire former Leichhardt LGA.

The former Leichhardt LGA includes the suburbs of Annandale, Balmain, Balmain East, Birchgrove, Leichhardt, Lilyfield, and Rozelle, and is roughly bounded by Sydney Harbour to the north, Parramatta Road to the south, Johnston Creek to the east and Hawthorne Canal to the West.

Whites Creek, Johnston Creek and Hawthorne Canal are the three major creek systems located within the LGA. Localised piped drainage systems throughout the LGA drain either to these main creek systems or drain directly to Sydney Harbour.

Flooding throughout the catchment is a combination of overland flow and mainstream flooding.

Mainstream flooding issues occur along the three main creek and channel systems of Whites Creek, Johnston Creek and Hawthorne Canal.

Elsewhere, flooding is primarily a result of overland flow. Although the majority of overland flow is collected and carried by the piped drainage network or by the kerb and gutter within the road reserve, there are some locations where overland flow passes across properties. This is typically where development has occurred next to natural flow paths, depressions, and low points.

Where the density of development has completely blocked the overland flow path - such as historical terrace housing development and townhouses - overland flow has no alternative than to pass through actual dwellings.

Community Input

Council recognises the importance of community consultation in the preparation of the FRMS&P.

Council’s goals for community consultation are to inform the community about the study, to identify community concerns and attitudes, to gather information from the community and to develop and maintain community confidence in the study results.

Public exhibition of the draft documents will be available for the community to view and have their say on the proposed options for flood management and risk mitigation. This feedback will be incorporated into the final document.

Council will let the community know when they can have their say. The draft Plans will be available at Council’s Service Centres in Leichhardt, at the Leichhardt and Balmain Libraries, and on this web site.

During consultation Council will hold community workshops and survey of residents on the proposed options.

Some of the key topics to be surveyed include:

  • General questions of knowledge of flooding in the catchment and expected flooding in the future.
  • Demographic information, which is useful for determining some of the social aspects of the study and for comparison with census data. This can then inform emergency management and evacuation strategies.
  • Ranking of potential mitigation options, which will help us understand your preferred options.
  • Interest in future information on the study to see whether respondents want to find our more in the future. This website will be available for the duration of the study preparation.

Past Studies

flood map purpleLeichhardt Flood Study


The Leichhardt Flood Study (Cardno 2014) identified the existing flood behaviour and associated hazards throughout the former Leichhardt LGA.

Using hydraulic models established by Cardno, the study determined the flood behaviour for the 100 year, 50 year, 20 year, 10 year and 5 year ARI design floods and the Probable Maximum Flood (PMF). The primary flood characteristics reported for the design events considered include depths, levels, velocities and flow rates. The study has also defined the provisional flood hazard for flood-affected areas.

The Study included survey and collection of over 3500 stormwater pits and pipelines together with cross sections of stormwater channels and culverts, and included a resident survey of approximately 22,000 property owners and occupiers, targeting local residents experience with flooding.

The Flood Study forms the basis for development of the Leichhardt FRMS&P.

pdf-new-icon.gif Leichhardt Flood Study (PDF 1.4MB)

View the draft documents of the plan below:

pdf-new-icon.gifDraft Leichhardt Flood Study - Volume 01  (PDF 8MB)
pdf-new-icon.gifDraft Leichhardt Flood Study - Volume 02 - Part A (PDF 9MB) 
pdf-new-icon.gifDraft Leichhardt Flood Study - Volume 02 - Part B  (PDF 8.7MB)
pdf-new-icon.gifForeshore Flood Control Lot Map - Central View (PDF 439KB)

pdf-new-icon.gifForeshore Flood Control Lot Map - Northern View (PDF 429.4KB)

pdf-new-icon.gifFlood Control Lot Map - Central View (PDF 505.4KB)
pdf-new-icon.gifFlood Control Lot Map - Northern View (PDF 446.6KB)
pdf-new-icon.gifFlood Control Lot Map - Southern View (PDF 543.3KB)

estuarine flooding balmain

  

Estuarine Planning Levels Study


The Leichhardt Estuarine Planning Levels Study (Cardno 2010) for the foreshore region of the former Leichhardt LGA defines storm tide, wave run-up and overtopping impact effects on water level for the foreshore areas of the former Leichhardt LGA. ,

Specifically, the study provides maximum water and wave impact levels for foreshore properties that may be generated by storm events during the 5 year, 10 year, 20 year, 50 year, 100 year and 200-years average recurrence interval (ARI) design conditions.

pdf-new-icon.gif  Estuarine Planning Levels Study (PDF 5.6MB) 

 

 

 

 

 

 

Parramatta River Estuary Coastal Zone Management Study and Plan

The Parramatta River Estuary Coastal Zone Management Plan (Cardno June 2013) investigated the key estuarine management issues and developed a series of management aims and objectives for the Parramatta River estuary on behalf of the Parramatta River Catchment Group (PRCG). The Parramatta River estuary commences at Balmain and is the main tributary of Sydney Harbour.

parramatta coastal estuary mapFive actions were included in the Coastal Zone Management Plan for the former Leichhardt LGA.

The floodplain management options proposed as part of the Leichhardt Floodplain Risk Management Study and Plan will consider the outcomes of the CZMP to ensure consistency between the two plans.

pdf-new-icon.gif  Parramatta River Estuary Coastal Zone Management Study and Plan (PDF 47.8MB) 

 

Whites Creek Catchment Management Study - Sydney Water - August 1990

The Whites Creek catchment rises in the south of the former Leichhardt LGA within the former Marrickville LGA. The southern portion of Whites Creek, between Parramatta Road and is a box culvert beneath Whites Creek Lane . The culvert discharges into an open channel between Booth Street and Piper Street, and eventually discharges into Rozelle Bay to the east of The Crescent.


Flooding in the area occurs along both the Creek itself and a number of overland flow tributaries that connect with the creek. The Whites Creek culvert tends to flow full in a 5 year ARI event. While the flowpath tends to follow Whites Creek Lane, the flooding does extend to the adjacent properties.

Downstream of the culvert section of Whites Creek, the creek is followed by parkland on both sides for the majority of the length. Flooding is primarily limited to the parkland, although a number of adjacent properties are affected.

A number of properties are impacted by overland flooding from tributaries to the main Whites Creek flowpath.

pdf-new-icon.gif  Whites Creek Catchment Management Study (PDF 2.4MB)

Johnston Creek Flood Study - Sydney Water


Johnston Creek also originates from the south of the former Leichhardt LGA. A large portion of Johnston Creek is also located within the City of Sydney LGA, including all areas north of The Crescent.

A short section of Johnston creek, between Parramatta Road and Water Street, Annandale, is a covered channel. Downstream of Water Street Johnston Creek is an open channel.

The Johnson Creek SWC 55 Capacity Assessment (Sydney Water, December 1995) “assessed the performance of various elements of the drainage system in terms of the average recurring design storm required for the corresponding peak flow to exceed the hydraulic capacity of the drainage path, ie channel plus any overbank capacity”.

Within the former Leichhardt LGA, the majority of the lands adjacent to Johnston Creek are parkland, which limits flood impacts on adjacent properties. However, some privately owned lands adjacent to Johnston Creek and its tributaries are also subject flooding.

pdf-new-icon.gif Johnston Creek Flood Study (PDF 1.8MB)

 

Development Controls

Flood related Development Controls


Flood related development controls are addressed in Part E - Water of Council's Development Control Plan (DCP 2013). The purpose of flood related development controls is to manage development on flood prone land to minimise or at least reduce the risk and consequence of flooding on that development. Typically the controls require the raising of floor levels, flood proofing of buildings and the provision of overland flow paths.

Changes to the flood control lot mapping in the Development Control Plan are available now for you to have your say. You can find them here:

Council’s development controls will be further reviewed as part of the Floodplain Risk Management Study.

Flood Lots White CreekFlood control lots


Flood control lots are those properties within the LGA that Council’s development controls apply to because of their potential to be affected by flooding. This does not necessarily mean that the properties are flood affected, simply that they potentially could be.

Typically, flood control lots may experience flooding from mainstream flooding, where flood waters rise up from creeks and / or flooding by overland flows from uphill lands.

Foreshore Flood LotsForeshore Flood control lots

Foreshore flood control lots are those properties within the LGA that Council's development controls apply to because of their potential to be affected by estuarine / tidal inundation and wave impact.

 

 

 

Flood Mapping Tool

This flood mapping tool allows you to investigate the flood extent, hazard, depth and velocity for the 1 in 100 year Average Recurrence Interval (ARI) flood event and the Probable Maximum Flood (PMF) event throughout the former Leichhardt Municipality.

You can investigate the elements of these floods either as a broad picture over the Municipality by zooming out on the screen, or in more detail by zooming in.

To access the web based mapping tool please click the link below:

Flood Mapping Tool

Flood Mapping Tool

The tool has been deliberately limited to show flood hazard, depth and velocity within roadways, parks and public open spaces.

On private property, only the flood extents are shown.

The level of detail provided on the mapping tool is not enough to form the basis of any reports required as part of a Development Application.

If you need more detailed information of the nature of flooding at or near a property you should apply to Council for a Flood Certificate.

Flood Certificates


Flood Certificates provide flood related information specific to the flood control lots and can be obtained from Council on application. The certificate provides information such as water levels, water depths, flow rates and hazard category and can be used to assist understand the extent of flooding which may affect a property.

The Flood Certificate can be used to inform the Flood Risk Management Report when it is required as part of a development application in accordance with Section E1.3 of DCP 2013.

The application form for a Flood Certificate can be found at the link below:

pdf-new-icon.gif Flood Certificate Application Form (PDF 136KB)

 

Remaining Study Timeline

Following are the key actions and dates for completion of the Leichhardt Flood Risk Management Study and Plan from March 2016

study table