Study in development

Following from the Manly to Seaforth Flood Study which assessed flood risk in the area, we are preparing a Floodplain Risk Management Study and Plan to help reduce the impacts of flooding for residents and businesses.

The study area includes the suburbs of Clontarf and Balgowlah Heights and parts of Manly, Fairlight, Balgowlah and Seaforth. It excludes the Manly Lagoon Floodplain.

This project is investigating a range of options to reduce flood risk in the study area and develop a long term plan for the management of flood prone land.

Between 11 May 2020 and 14 June 2020 we gathered feedback from the community via an online survey. 149 surveys were completed, thank you to everyone who provided feedback.

As we undertook a rigorous engineering and cost analysis process, your input helped us further develop our understanding of the local context.

An assessment of flood mitigation options has been completed by the consultant and the development of the study, including recommendations, is in its final stage.

The draft study and plan is expected to be presented to Council later in 2023 for approval to exhibit. During the public exhibition, the community will have the opportunity to discuss the results with Council staff and the engineering consultants.

Study Area

We are investigating and managing the natural flooding caused by significant catchment rainfall resulting in overland flow - water that runs across the land after rain, before it enters a creek, harbour or the ocean.

A floodplain is any portion of land which is subject to inundation by floods up to and including the Probable Maximum Flood (PMF) event (or the highest conceivable flood that can occur).

A Flood Planning Area (FPA) is the land where residential flood related development controls apply.


Council recently commissioned engineering consultants WMA Water to complete a comprehensive Floodplain Risk Management Study for the area.

This study will consider a range of flood management measures, such as structural options (bigger pipes, detention basins etc.), emergency management improvements, community awareness activities and land use planning. The options will be assessed to understand the potential impacts and benefits, with a final suite of recommended options presented in the Manly to Seaforth Floodplain Risk Management Plan.

The main objectives of the floodplain risk management process are to:

  • minimise risk to life, health and safety
  • reduce flood damage to property and infrastructure in the existing community
  • ensure future development is controlled in a manner which is compatible with a catchment's flood risk
  • protect and enhance the floodplain environment and be consistent with relevant State Government policies
  • ensure that the Floodplain Risk Management Study and Plan has the support of the local community.

This project is supported by the NSW Government’s Floodplain Management Program.


  • Timeline item 1 - complete

    May/June 2020 - Community Survey

    Survey closed: Sunday 14 June 2020

  • Timeline item 2 - incomplete

    Public exhibition of the draft Study and Plan

    Includes community information sessions

  • Timeline item 3 - incomplete

    Report to Council

Have an enquiry?

Name Patrick Stuart, Team Leader, Floodplain Planning & Response
Phone 1300 434 434 (during business hours)