Featured artist: Shannon Crees

Flood management

Featured artist: Shannon Crees

Community

Flood management in Marrickville

The nature of flooding in Marrickville

The former Marrickville local government area straddles two main catchments: The Cooks River Catchment and the Port Jackson Catchment.

Around 75% of the local government area discharges to the Cooks River, with the remaining 25% discharging through the former Leichhardt and the City of Sydney local government areas to Port Jackson. Generally, storm water south of New Canterbury Road and Enmore Road flows to the Cooks River, while storm water north of New Canterbury Road and Enmore Road flows to Port Jackson.

The low lying areas of Marrickville were once covered by a large natural wetland called the Gumbramorra swamp. The area also contained numerous ephemeral creeks leading to the Gumbramorra swamp, the Cooks River and Port Jackson.

The role of the creeks and the Gumbramorra Swamp in the ecological system was not fully understood or appreciated and, as the area developed, these creeks were piped or channelised and the swamp was drained to facilitate the industrialisation of the suburb.

Many of the areas affected by flooding today are around these old creek lines or in low lying areas which would have once been swamps. Flood management plans need to be put in place to safeguard these flood prone areas during storms. These plans aim to manage flood affected areas, through responsible development and drainage infrastructure, to reduce the risk of future flooding.

There are two main types of flooding in the Marrickville area:

  • Flooding of the Cooks River, also called mainstream flooding, where the River breaks its banks inundating low lying areas adjacent to the River; and
  • Overland flooding, where water flows along natural or man-made drainage paths through streets and properties on its way to the Cooks River or Port Jackson.

Much of the flooding experienced in the Marrickville area is due to overland flooding and typically occurs when short duration storms dump a large amount of rainfall in a short space of time, typically less than an hour, and the drainage system cannot cope. Long duration storms, where steady rain falls over a day or more, can typically be contained within the drainage system.

The flood planning process

It is a legal requirement for councils to address flooding issues under the NSW Government's Flood Prone Land Policy:

  1. The Flood Study – collates available data and determines the nature and extent of flooding for a range of flood events up to the Probable Maximum Flood (PMF).
  2. Floodplain Risk Management Study – identifies and evaluates management options to reduce the risk of flooding
  3. Floodplain Risk Management Plan – involves development of a plan of management for flood affected areas for adoption by Council.
  4. Implementation of the plan – Involves implementation of measures to reduce the risk of flooding. Examples of such measures are:
    • Improving drainage flow paths
    • Upgrading storm water pipes and pits to direct floodwater away from homes.
    • Implementation of community awareness programs
    • The development of policies to ensure new development is constructed in a manner compatible with the flood hazard.

Council is progressively completing flood management plans across the local government area. The progress of the flood planning process in each catchment area is detailed below.

Council welcomes feedback from the local community. Residents, businesses and owners directly in the area of each plan will be notified and engaged during the preparation of the plans. The wider public is invited to view and comment on the draft plans when they are presented for exhibition.

Alexandra Canal

The Alexandra Canal Catchment covers parts of the suburbs of Tempe, Sydenham and St Peters. The overall area covered by the plan is approximately 200 hectares and the land uses are a mix of residential, commercial, industrial and parklands. The catchment area is approximately bounded by the Princes Highway and the Alexandra Canal.

The upper part of the Alexandra Canal catchment is managed by the City of Sydney. Details for this area can be found here.

The Alexandra Canal Flood Study was adopted by Council in June 2017. The documents are available for download below. The Alexandra Canal Floodplain Risk Management Study and Plan is planned to commence in 2020.

Cooks River

The Cooks River Flood Study and Management Plan is different from all other studies completed by Marrickville in that it looks at the risk of the Cooks River breaking its banks and flooding. All other studies look at overland flooding, where water flows along natural or man-made drainage paths through streets and properties on its way to the Cooks River or Port Jackson.

The Cooks River Flood Study was completed in 2009 by Sydney Water in collaboration with numerous Councils. The Cooks River Floodplain Risk Management Study and Plan for the Marrickville area was adopted by Council in February 2015.  The documents are available for download below.

Eastern Channel East

The Eastern Channel East Catchment area covers parts of the suburbs of Newtown, St Peters, Enmore and Marrickville. The overall area covered by the plan is approximately 135 hectares and the land uses are a mix of residential and commercial. The catchment area is approximately between south King Street and Enmore Road.

The Eastern Channel East Catchment is part of the Marrickville Valley Catchment (refer below). The Eastern Channel East Management Plan was completed as a pilot to integrate the floodplain risk management process with water sensitive urban design objectives.

The Eastern Channel East Flood Study and the Eastern Channel East Floodplain Risk Management Study and Plan were adopted by Council in February 2012.  The documents are available for download below.

Hawthorne Canal

The Hawthorne Canal Catchment area covers parts of the suburbs of Dulwich Hill, Lewisham and Petersham. The overall area covered by the plan is approximately 210 hectares and the land uses are a mix of low and medium density residential. The catchment area is bounded approximately by New Canterbury Road and Old Canterbury Road.

The lower part of the Hawthorne Canal catchment is managed by Ashfield and Leichhardt Councils. Details for this area can be found here.

The Hawthorne Canal Flood Study was adopted by Council in February 2015. The documents are available for download below. The Hawthorne Canal Floodplain Risk Management Study and Plan is planned to commence in 2017.

Johnstons Creek

The Johnstons Creek Catchment area covers parts of the suburbs of Camperdown, Newtown, Enmore, Stanmore and Petersham.  The overall area covered by the plan is approximately 215 hectares and the land uses are a mix of medium density residential and commercial. The catchment area is bounded approximately by Enmore Road and New Canterbury Road and Parramatta Road.

The lower part of the Johnstons Creek catchment is managed by the City of Sydney. Details for this area can be found here.

The Johnstons Creek Flood Study was adopted by Council in June 2017. The documents are available for download below. The Johnstons Creek Floodplain Risk Management Study and Plan is planned to commence in 2019.

Marrickville Valley

The Marrickville Valley Catchment area covers parts of the suburbs of Marrickville, Sydenham, Enmore, Dulwich Hill, Petersham and Stanmore.  The overall area covered by the plan is approximately 660 hectares and the land uses are a mix of residential, commercial and industrial. The catchment area is bounded approximately by New Canterbury Road, Princes Highway, the Cooks River and Stanmore Road. The Marrickville Valley Flood Study and management Plan excludes the Eastern Channel East catchment which was completed as a separate plan (refer above).

The Marrickville Valley Flood Study was adopted by Council in April 2013. The documents are available for download below.

The Marrickville Valley Floodplain Risk Management Study and Plan commenced in October 2015. Find out more here.

South Marrickville

The South Marrickville Catchment area covers parts of the suburbs of Marrickville and Dulwich Hill.  The overall area covered by the plan is approximately 200 hectares and the land uses are a mix of residential and parklands. The catchment area is bounded by the Cooks River in the south and Warren Road and Old Canterbury Road in the north.

The South Marrickville Flood Study is planned to commence in 2018.