North Creek Flood Study

A flood study is a comprehensive technical investigation of flood behaviour that will provide the main technical foundation for the development of a future floodplain risk management study and plan for the catchment.

The study will aim to provide an understanding of the full range of flood behaviour and flood events for the North Creek catchment study area. It involves consideration of the localised flood history, available collected flood data, and the development of hydrologic and hydraulic models.

The outputs of the study should assist Council by providing a better understanding of:

• flood behaviour, flood hazard and flood risk in the study area
• defining hazard areas and producing probability flood level information to assist Council with future developments in Warners Bay
• impacts and costs for a range of flood events or risks on the existing and future community
• impacts of changes in development and climate change on flood risk
• emergency response requirements for the study area
• effectiveness of current management measures
• facilitating information sharing on flood risk with the Warners Bay community
• understanding future flood scenarios incorporating climate change.

North Creek has a catchment area of 5.3 square kilometres and flows into Lake Macquarie at Warners Bay.

The North Creek catchment incorporates residential development (50 per cent), non-residential development (10 per cent, largely schools and commercial/light industrial), open space and forested areas (40 per cent).

The creek has two main tributaries, the western and eastern tributaries. Each of these has a sub-branch, Seaman Avenue on the western tributary, and the King Street and Lakelands branches on the eastern tributary.

North Creek Flood Study area

Yes, this flood study will build on the work already completed as part of the 2005 North Creek Flood Study and 2010 North Creek Floodplain Risk Management Study.

Council has engaged specialist consultant WMAwater to undertake the North Creek Flood Study.

The NSW Flood Prone Land Policy aims to reduce the impacts of flooding and flood liability on communities, reduce the private and public losses resulting from floods and increase community resilience to floods. The management of flood-liable land is primarily the responsibility of local government. The NSW Government provides guidance to councils on how to achieve this through the Flood Risk Management Manual 2023 (the Manual). The Manual outlines the flood risk management process as follows:

1. Data collection
2. Flood study
3. Flood risk management study
4. Flood risk management plan.

The draft North Creek Flood Study constitute the first and second stages of the flood risk management process, being data collection and a flood study.

In Lake Macquarie City, there are 10 major catchments feeding into the lake and Council has adopted flood studies and flood risk management plans for all of the major catchments and most of the minor catchments.

The results of the study should assist Council by providing a better understanding of flood behaviour, flood hazard and flood risk in the study area to both allow Council and other agencies to plan and manage these risks based on the best possible information.

In accordance with the NSW Flood Risk Management Manual, the properties that are identified in the flood study as being impacted by the one per cent annual exceedance probability flood event are designated and conditioned as Flood Control Lot - High Hazard. These properties will be subject to flood planning controls, allowing for an appropriate freeboard if required.

Flood information will also be made available on Section 10.7 planning certificates to let existing and future owners know that a property may be potentially flood prone, up to and including the Probable Maximum Flood (PMF) event.

The annual exceedance probability (AEP) is the chance of a specific size flood occurring in any one year, expressed as a percentage. A one per cent AEP flood has a one per cent or 1 in 100 chance of being reached or exceeded in any given year.

Insurers use data from a variety of sources including historical flood measurements, Federal, State and Local government studies, the Insurance Council of Australia’s National Flood Information Database and their own research (i.e. own assessment of risk). In essence, different companies will assess the risk in different ways and Council does not control what flood data insurers choose to use or how they use it. Over the past few years, a number of factors have combined to raise the price of flood cover and insurance more generally. These include:

• the cost of claims generated by the series of major disasters (including storms, flooding and bush fire) since 2010

• Australian insurers paying more for reinsurance (insurance that insurers take out to cover major events) because of these disasters

• changes in understanding where and when floods will occur and how much it costs to fix damage.

The Insurance Council of Australia advised Council that people should shop around if they are dissatisfied with the cost or coverage of their flood insurance. Residents are also advised to look carefully at what they are covered for, rather than just basing their decision on the price. For further information on insurance, residents can visit: About us - Insurance Council of Australia.

Flooding of roads and residential areas within the North Creek catchment has occurred on several occasions in living memory, the most notable being June 1949, February 1990, June 2007 and April 2015.

At the start of the project, the landowners in the study area received a letter with information about the project and the opportunity to share their observations and experiences of flooding. The wider Lake Macquarie community were also given the opportunity to find out about the project and contribute feedback via Council’s online community engagement platform, Shape Lake Mac. Community consultation ran from 29 November 2023 to 10 January 2024. A total of 11 responses were received. A summary of engagement can be viewed online. 

Feedback may result in changes being made to the Draft Flood Study prior to a report being prepared for Council.

You will be notified again, prior to Council considering the matter, which will include a link to the Council report containing a summary of submissions and how feedback was considered.