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Background

Wakehurst Parkway is one of the main road connections on the Northern Beaches passing through Narrabeen, Oxford Falls, Frenchs Forest, and North Balgowlah.

While an important thoroughfare for our community, the areas surrounding Wakehurst Parkway (the Parkway) have significant cultural heritage and environmental values associated with the adjoining bushland and riparian areas.

Local residents will be aware that the Parkway north of Warringah Road is prone to flooding in certain areas and has historically experienced frequent road closures as a result. At present, this is up to six to seven times per year on average. Check out the overview of the key drivers of flooding for more information.

The draft Wakehurst Parkway Flood Mitigation Feasibility Study (draft feasibility study) was recently completed with grant funding through the NSW Government Stronger Communities Fund to explore options to help protect the road from flooding.

The draft feasibility study explores options to address key problem flooding sites along the Parkway outlining indicative costs and potential environmental considerations. The options were evaluated across four potential levels of flood protection.

We have developed a comparison table showing the effectiveness, and potential constraints and impacts of each option to achieve different levels of flood improvement for the Parkway.

Based on the findings within the draft feasibility study the most effective solution to manage frequent flooding would be to implement the combination of options B4, O2 and S1 (as outlined in the comparison table). These options are designed so that the Parkway (north of Warringah Road, would only close in storm events exceeding a 1 in 2 year Average Recurrence Interval (ARI). However these options result in significant environmental impacts.

Transport for New South Wales (TfNSW) has agreed to provide additional funds that allow us to implement the above options as a project, should Council decide to proceed.

If this project progresses past the current stage, further environmental investigations, project planning, detailed design and delivery would all need to be undertaken.

This project, if it proceeds, is expected to have environmental impacts which will be assessed in the next stage of the project. Council is committed to exploring ways to ensure the local and unique ecological character of the Middle Creek catchment and the Parkway area is appropriately rehabilitated and maintained into the future.

We want to know your thoughts

We appreciate the draft feasibility study is lengthy and technical. The options assessment process and identified outcomes have been broken down on this page to help you navigate through the information.

Please click the tabs below to learn more and have your say. The full feasibility study (parts 1 and 2) are available in the Document library.

We encourage you to read through this page and tell us whether you think we should proceed with the options noted above, any other option or combination of options that would reduce the frequent flooding of the Parkway. We also welcome views on suggested alternatives.

Your feedback will directly inform our recommendations which will be reported back to the elected Council who will determine whether to proceed with the next stages of the project.

If you have questions, would like more specific information or need assistance with this page, please email us.

We will be holding three information sessions this month:

1) Thursday 17 June: Online

2) Saturday 19 June: Bilarong Reserve, Narrabeen

3) Tuesday 22 June: The Tramshed, Narrabeen

Options detailed

Flood improvements for Wakehurst Parkway

The draft feasibility study details a set of options that could be used in combination to provide varying levels of flood improvements.

We have prepared a table to show the comparison of options needed to achieve different levels of flood improvements for the Parkway.

Options comparison table

The Parkway

About Wakehurst Parkway

Wakehurst Parkway is a state-owned arterial road and popular commuter route in the Northern Beaches. The Parkway runs through an area of high environmental significance.

An important connection

The Parkway serves as a key route for commuters travelling to and from the Sydney and Parramatta CBDs and key commercial districts including Chatswood and North Sydney in the morning and evening weekday peaks (linking drivers eventually with the Pacific Highway to the west and Pittwater Road to the south and east). It also acts as a key transport link in the area providing an alternative connection to using Mona Vale and Pittwater Roads.

The Parkway north of Warringah Road is prone to flooding, with road closures typically six to seven times a year. This frequent flooding typically occurs when Middle Creek’s floodplain fills up, triggered by heavy rainfall. TfNSW estimate 8,000 trips daily on average depending on time of day and week, and an average road closure of around five hours. During flood events, this can impact hundreds of drivers an hour.

An environmental and culturally sensitive area

The riparian corridor in the Creek is recognised as Key Fish Habitat by the Department of Primary Industries (DPI). Seven different plant community types are found in the area, including threatened ecological communities (TECs), and the set of options has the potential to affect four habitats identified as TECs under the Biodiversity Conservation Act 2017.

Fifteen threatened fauna species were found to likely use the environment between the Parkway and Middle Creek as foraging habitats. These are:

  1. Red-crowned Toadlet.
  2. Giant Burrowing Frog.
  3. Eastern Osprey.
  4. Glossy Black Cockatoo.
  5. Varied Sittella.
  6. Black Bittern.
  7. Powerful Owl.
  8. Sooty Owl.
  9. Little Bentwing-bat.
  10. Eastern Bentwing-bat.
  11. Eastern Freetail-bat.
  12. Southern Myotis.
  13. Grey-headed Flying-fox.
  14. Large-eared Pied Bat.
  15. Rufous Fantail - migratory under the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC).|

Overview of environment considerations


The Parkway is prone to flooding

The Parkway north of Warringah Road is prone to flooding with road closures typically six to seven times a year. This frequent flooding occurs when Middle Creek's floodplain fills up, triggered by heavy rainfall.

The maps below shows the three sites along the Parkway that have been found to be more flood-prone. The options in the draft feasibility study target these sites in order to reduce flooding.

Overview of flooding along the Parkway

Options refinement

Options assessment process

Over a period of several years, TfNSW and Council have investigated flooding along the Parkway.

With funding from the NSW Government Stronger Communities Fund, Council commissioned investigations to:

  • understand the nature and key drivers of flooding on the Parkway
  • understand potential options that could be implemented
  • assess and understand the impacts of these options.

Investigations were conducted in phases with the initial data collection taking place over 2017 to 2018 and further detailed assessments happening in 2019. These informed an options assessment process, which included identification and assessment of a long list of options, and two rounds of shortlisting.

Council wrote to TfNSW to seek additional funding in December 2019. A formal funding offer from TfNSW to proceed was received in February 2021. Since then, Council finalised the draft feasibility study, presented it to the elected Council in March 2021 and it is now on public exhibition.

The figure below provides a snapshot of the options assessment process with an overview of the options that were considered feasible to progress and those that were excluded at each stage (indicated by strike-through text).

The full list of investigations can be found in Section 3 of the draft feasibility study.

Short listed options across the three sites

The following section details the viable shortlisted option for each flood affected site including Oxford Falls, the Bends and the Sydney Academy of Sports and Recreation.

Next steps

Next steps

While a lot of work has been completed, there are a number of steps to come. If the elected Council decides to proceed, further designs and environmental approvals are required for the preferred option, or combination of options.

Feedback collected during this consultation period will be collated, assessed and reported back to Council.

Future stages of any flood reduction project would include, but not be limited to:

  • community consultation
  • design and approvals
  • procurement
  • construction and ensuring the rehabilitation of the impacted area.

Thorough community and stakeholder engagement would be completed across all future project stages.


Have your say

We encourage you to read through this page and tell us whether you think we should proceed with the project (combination of options B4, O2 and S1) or any other option or combination of options that would reduce flooding on the Parkway.

No commitment has been made at this stage to pursue any specific option or combination of options and we want to hear from our community prior to making a decision.

We invite your feedback. You can have your say by:

  • completing the comment form below
  • emailing us at council@northernbeaches.nsw.gov.au
  • writing to us marked 'Wakehurst Parkway Flood Mitigation', Northern Beaches Council, PO Box 82 Manly, NSW 1655.

Submissions close Sunday 27 June 2021.

Comment form

Photo credit: UNSW Water Research Laboratory - Chris Drummond