Following concerns raised by residents during the public exhibition of the draft amendment in 2022, Council:

• engaged a consultant to undertake an independent peer review of the Waverley Flood Study and draft DCP amendment,
• engaged a consultant to undertake an independent review of the potential impacts on property prices,
• researched the potential insurance implications for residents,
• contacted residents who raised concerns or provided a submission on the Draft Amendment, and;
• hosted an online webinar for residents to explain the findings and for residents to ask questions.

As a result of the additional work undertaken in 2023, several changes were proposed to the Waverley Development Control Plan (DCP) draft amendment relating to floods, this includes:

• changes to the flood maps which result in a reduction of private land area affected, and
• changes to provide for more flexibility in the application of flood-related planning controls in the DCP.

The revised amendment was reported to the Council Meeting on 19 March 2024. and adopted.

Findings of the peer review

The peer review concluded that the approach and methodology used to prepare both the Waverley LGA Flood Study and associated draft DCP amendment were considered as reasonable and in-line with best practice and all relevant State Government guidelines. In considering improvements which could occur in the Peer Review, a number of recommendations were made which Council will undertake including:

- Undertaking further investigation of any limitations within the flood modelling as part of the subsequent Floodplain Risk Management Study and Plan (FRMSP),

- Changing the Flood Risk Precinct flood maps to include the actual extents of flood risks across a lot, rather than colouring in the entire lot as within either Low, Medium or High FRP.

- Including performance criteria in the planning controls to provide some flexibility for different types of development and situations.

You can also read and download the full report with the full findings.

Findings of Property price impacts

The FAQ further below provides discussion about the research undertaken relating to insurance implications. You can also read and download the full report with the full findings.

Findings of research on insurance implications

The FAQ further below provides discussion about the research undertaken relating to property price implications. You can also read and download the full report with the full findings.

Changes to the flood maps and draft amendment

In response to concerns raised and additional work completed, the adopted DCP has been revised and includes changes to the flood maps which result in a reduction of private land area affected as well as providing for more flexibility in the application of flood-related planning controls in the DCP.

The Waverley LGA Flood Study outlined that most of the water where inundation could occur, aside from Bronte Gully and Tamarama Gully, in the Waverley LGA should be considered as ‘stormwater’ for the purposes of insurance. In Australia, all insurers have adopted a consistent definition of a flood as:

‘The covering of normally dry land by water that has escaped or been released from the normal confines of any lake, river, creek or other natural watercourse, whether or not altered or modified; or any reservoir, canal or dam’. Stormwater is not considered a ‘flood’ for insurance purposes.

Simplistically, stormwater damage is associated with water travelling to a watercourse or water body, while flood damage is associated with water travelling from a watercourse or water body.

Insurance premiums for specific properties and addresses are determined by individual insurance companies based on their assessment of risk and probability of damage – based on best available research, as well as historical events in an area – and are outside of Council’s control.

However, following concerns raised by residents, Council has undertaken research to determine what impacts the draft DCP could have on insurance premiums, to ensure that any implications have been considered. The findings of the research also concluded that there was no clear correlation between flood risk related planning controls and mapping and increased insurance premiums and that a variety of factors influence insurance premiums provided by insurers.

You can read the full findings of the research Council undertook on insurance by downloading the report.

If you think an insurer has assessed your flood risk incorrectly, you can read the advice the Insurance Council of Australia has provided in the below FAQ.

The Insurance Council of Australia recommends that if you believe a flood premium has been incorrectly charged that you investigate the following:

If you have evidence that an insurer has incorrectly assessed risk of flooding (e.g. a Council flood study, floor level survey, site-specific flood report or similar), please contact the insurer directly to discuss. Many major insurers have dedicated flood premium review processes in place and welcome information that helps improve the accuracy of their flood risk assessments. The Insurance Council of Australia (ICA) can also assist in reviewing information if an insurer cannot. Providing the insurer or ICA documentation will assist in this discussion.

It is also important to shop around if you are not satisfied by the premium or cover offered by your insurer.

When discussing your insurance premium and potential flood component of your insurance, you may wish to refer to the description from the Waverley LGA Flood Study which states that most of the water where inundation could occur, aside from Bronte Gully and Tamarama Gully, in the Waverley LGA should be considered as ‘stormwater’ for the purposes of insurance.

Since the draft amendment was exhibited, Council commissioned a review of potential property price impacts which concluded that adoption of new flood maps would unlikely have an impact on property prices and also that previous flood maps which were present in Council’s LEP had no impact on property values. You can read and download the report with the full findings for more information.

It is a requirement to have information on flooding in Section 10.7 Planning Certificates that Council is responsible for issuing. Section 10.7 Certificates are a requirement for the transaction of a property and are typically attached to a contract of sale.

Properties previously marked on the Flood Planning Area maps in Council’s Local Environmental Plan (LEP) had this information available on these certificates since the maps were included in the LEP in 2012. Information relating to properties marked on the draft DCP amendment maps has been included on these certificates since it was placed on public exhibition in June 2021 and will remain until the DCP comes into effect. Properties tagged as part of the Waverley LGA Flood Study also contained notations on Section 10.7 Certificates during and following the public exhibition period.

After a period of four years of technical investigations and community engagement, Council adopted the Waverley LGA Flood Study in 2021. The study identified flood affected areas based on up-to-date modelling techniques. It was the first step in Council fulfilling its obligations as part of the Floodplain Risk Management Process set by the NSW Government.

Shortly after the adoption of the Flood Study, the NSW Government introduced the Flood Prone Land Package, which brought in changes to the way flood planning is addressed in the Waverley Local Environmental Plan (LEP) and Development Control Plan (DCP). As a result, DCP controls were reviewed and updated to ensure that the risks and impacts of flooding associated with any new development or redevelopment would be appropriately managed. The new flood maps are required for the application of both the LEP and DCP flood related planning controls.

There are a number of reasons why your flood risk precinct rating could differ from that of neighbouring lots:

• There may be an overland flow path through your lot, while your neighbours lots may only be within the ‘flood fringe’, or outside the flood extent. This would have triggered your lot to be mapped with a higher flood risk precinct rating than your neighbours due to the likelihood and consequence associated with these differences.
• The flood affectation on either lot may have a higher or lower hazard classification. Hazard classifications are based on the depth and velocity of the overland flow. The hazard classifications influences the flood risk precinct. The thresholds are related to the effect of flood waters on the stability and danger to both people and vehicles, and to the structural integrity of buildings.

Since the draft amendment was exhibited, changes have been made to the draft flood maps which have resulted in a reduction of the overall land affected by the maps across the LGA.

The Waverley LGA Flood Study was prepared in accordance with contemporary flood modelling techniques considering different rainfall intensity events. In accordance with industry standards, the study defined the 20% Annual Exceedance Probability (AEP) event (formerly referred to as a 1 in 5 year rainfall event), the 5% AEP event (formerly referred to as a 1 in 20 year rainfall event), the 1% AEP event (formerly referred to as a 1 in 100 year rainfall event) and the Probable Maximum Flood (PMF) event (the largest flood that could conceivably occur at a given location based on the meteorological and hydrologic conditions conceivably possible for the region).

The flood maps determined from these modelling exercises formed the basis of the flood study mapping and associated planning controls. These are the theoretical flood extents which are statistically expected to occur in any given year based on the best available information today.

For context in relation to the weather events described above, the storms in February 2022 were approximately equivalent to a 5% AEP event. It is likely that the flood event in November 1984 in the Waverley LGA was approximately equivalent to a 1% AEP event, when many properties within the LGA experienced flooding from the intense rainfall which occurred. Rarer more severe flooding can occur. Despite living in your property for many years, it is not unreasonable for you not to have witnessed these more significant rainfall events

There are two types of flood risk: mainstream flooding, where water comes out of a creek, river or other watercourse/waterbody, and overland flow, where rainfall runoff is making its way towards a watercourse/waterbody.

The Waverley LGA predominantly has overland flow, where rainfall runoff is making its way towards a watercourse/waterbody. This is the type of flooding which is likely to have been identified as impacting upon your property if your house is on a hill.

Overland flow is generally shallow, can be fast flowing, occurs during heavy rain events and passes soon after the rain stops.

It is important that new developments or redevelopments are designed with their overland flow flood risk in mind. Some considerations include:

• Ensuring overland flow paths are not obstructed – this can result in nuisance flooding of buildings with low entries such as garages, and make flooding worse for neighbours and public areas, such as footpaths and roads, by obstructing or diverting flow paths;
• Driveway entries being designed to keep overland flow in the gutter rather than overtopping and coming down into basements or low lying rooms;
• •Floor levels designed to ensure runoff doesn’t enter the home causing damage and frustration.

There is minimal mainstream flooding in the Waverley LGA, restricted primarily to Tamarama Gully and Bronte Gully. Note, for insurance purposes, overland flow flooding is primarily not considered ‘flooding’. You can read more about insurance and flooding here in the above FAQs on insurance.

The Flood Risk Precincts apply to the land or part of the land, not individual apartments within the building.

This means that if the building on that lot was to be redeveloped in the future, the developer would need to be mindful of the flood risk on the site and related planning controls when designing the new building.

Many parts of Council’s DCP contain technical information that might not always be easy for everyone who is not an expert in the relevant field to understand. The DCP has been prepared in a way in which was meant to be easy to read, use and implement. Following the draft exhibition of the DCP amendment, Council has commissioned a peer review which has recommended minor changes to the mapping associated with the Flood Risk Precincts in order to provide a clearer connection between the initial modelling outputs, expected flood extents and the flood risk categorisation selected, as well as many other simplifications to the DCP. You can read and download the report with the full findings of the peer review.

If you are undertaking a development you would typically engage professionals (for example a town planner or architect) who will be able to assist you in understanding the planning controls that would apply to your particular proposed development. Council’s stormwater team will also be able to answer generic questions about the contents of the DCP, but you would need to obtain specific guidance from relevant professionals on how your development should respond to Council’s planning controls.

The aim of the new DCP Flood Chapter and Flood Risk Precinct mapping is to apply a risk-based approach based on the sensitivity of different land uses to flood risk and to ensure that planning controls are better aligned to the level of risk on each lot (if any). The draft DCP planning controls address things such as, but not limited to:

• height of floor levels
• structural soundness of a property
• car parking and driveway access
• evacuation and fencing

For a Development Application, applicants will have an opportunity to demonstrate that their proposed developments will not be affected by flood waters and/or will not adversely affect flood behaviour elsewhere, impacting their neighbours or the wider community.

The flood modelling outputs from the Waverley LGA Flood Study were adapted to categorise lots as either part of a low, medium or high Flood Risk Precinct, which cumulatively represent all of the lots with proposed flood related planning controls. The planning controls differ based on the sensitivity of the land use to flood risks and the location of the land within the floodplain.

Since the draft amendment was exhibited on Council’s Have Your Say page between 23 June – 21 July 2022, Council commissioned a peer review which has recommended changes to the mapping associated with the Flood Risk Precincts and the DCP controls. You can read and download the report with the full findings of the peer review.

Preparation of the Flood Risk Precinct (FRP) mapping categories and associated DCP controls involved research on the approach undertaken by other Council’s across Sydney and New South Wales more broadly, and what would be considered best practice. The FRP risk based approach selected has been applied by approximately almost 40% of Council’s in the Greater Sydney, and is consistent with the State Government’s requirements. The approach taken to select the FRP categories has been verified as best practice by the independent Peer Review undertaken. You can read and download the report for more information on the full findings.

The proposed Flood Risk Precincts, adopted by Council, may be further reviewed when Council undertakes a further step in the NSW Flood Risk Management process and prepares a Floodplain Risk Management Study and Plan (FRMSP). Areas of uncertainty within the floodplain will be explored in greater detail when the FRMSP commences over the coming 12 months.

As a result of the Waverley LGA Flood Study and triggered by the NSW Government’s reforms, Waverley's Development Control Plan (DCP) was revised to ensure that new development/redevelopment in the area properly addresses and manages flood risk.

The Flood Risk Precincts map and planning controls use our improved understanding of flood risk to manage future development effectively. Constructing new developments to higher standards, utilising raised floors and flood-proof materials, can minimise the impact of heavy rainfall events on properties. The goal is to prevent future flood damage, minimise costs and danger for residents and property owners, and avoid transferring flood risk to neighbouring properties and/or the broader community.

Type A, B and C categorisations were categories used by the consultant (BMT) who prepared the initial Waverley LGA Flood Study in 2021 to explain the level of uncertainty typically reflected by overland flow flood modelling. The Flood Risk Precinct (FRP) categorisation (Low, Medium and High) is a categorisation process which aligns with a best practice methodology adopted by many Council’s in NSW for the purposes of applying flood related planning controls.

The Low, Medium and High risk FRP categorisations are based on information derived from the Flood Study, for the purposes of applying planning controls to development, that reflect a risk based approach.

Following completion of the updated flood modelling exercise and implementation of the associated planning controls in the DCP. Council will progress to the next stage of the NSW Flood Risk Management program, developing Waverley’s Floodplain Risk Management Study and Plan. This will involve more detailed investigation into the areas of more frequent and problematic flooding in the LGA and identification of ways of mitigating/reducing these flood impacts. Waverley Council has successfully secured State funding for this next stage in the process, which is expected to proceed over the coming 12 months. This process will be guided by Council's Floodplain Risk Management Committee. Interested residents were invited to have an opportunity to express their interest in participating in the committee and this process has now been completed.

Common to urban areas across Australia, Council stormwater assets which people would be familiar with (kerb and gutter, stormwater entry pits and underground pipes) are typically designed to cater for smaller, more frequent rainfall events, in the order of a 20% AEP event (formerly referred to as a 1 in 5 year rainfall event). In some areas of Waverley Council this stormwater infrastructure is designed to cater for larger storm events up to a 10% AEP event (1 in 10 year rainfall event). Rainfall events more sever than this are typically conveyed within roadways and through low lying open space areas (parks and ovals).

The larger stormwater drains and infrastructure (such as those which discharge at our many beaches) are typically owned, managed and maintained by Sydney Water. Council does own and manage a few of these larger stormwater drains as well. These drains receive the flow from all of the surrounding smaller Council drains before discharging to the ocean or local creeks. These drains are also designed to carry only a certain sized event and their capacity is often exceeded during more significant rainfall events with the drain running full and backing up into the catchment. When this occurs, it can mean that water from the Council owned stormwater drains cannot discharge freely and can result in short term ponding and inundation back upstream within the catchment.

Council stormwater assets are not designed to convey all rainfall events. Works undertaken by Council to minimise flood impacts are just one action that can be taken to manage flood risk. Depending on the specific property and the localised flood behaviour the works undertaken may not necessarily eliminate flood risk. Council is however assessing areas where flooding impacts on private property and where possible investigating options to reduce these impacts. Council will also reassess mapped flood risk precincts where large capital works projects have an improved outcome as determined by revised modelling, and update these maps accordingly. This may result in changing category to the flood risk precincts in the future.

The intention of this sentence in the letter distributed in June 2022 was to explain that the Waverley LGA Flood Study was completed and formally adopted by Council in 2021. The results from the Flood Study were used as the basis for the production of the Flood Risk Precincts to be used in the implementation of the planning controls. The draft DCP preparation and adoption process will not change the adopted Flood Study, however the modelling and outputs have been independently peer reviewed and verified as being consistent with industry guidelines and standards and reasonable and appropriate for the catchment.

The proposed Flood Risk Precincts may be further reviewed when Council undertakes a further step in the NSW Flood Risk Management process and prepares a Floodplain Risk Management Study and Plan. At that stage any areas of uncertainty within the catchment will be explored in greater detail.

Previous community consultation was undertaken for the Waverley LGA Flood Study in two rounds between 2017-2021. Flyers were provided to approximately 31,000 households and businesses, community information sessions were held, and Council also undertook resident interviews and questionnaires and promoted the Study via other Council channels such as social media and online newsletters. You can read the full details of the consultation undertaken; you can read consultation report on Council’s Have Your Say Page.

Waverley Council endorsed the Waverley LGA Flood Study in 2021 which included information on the Clovelly catchment which extends into the Randwick City Council LGA. Given the Flood Study would also need to be adopted by Randwick City Council, Randwick City Council has exhibited the Flood Study for comments by their community (i.e. those located within the Randwick LGA). The Flood Study report was subsequently amended in the relevant chapters related to the Clovelly catchment with further clarifying information for their community. The Randwick version of the Flood Study does not affect the Waverley Council outputs and can be clearly identified as it contains the Randwick City Council logo on the cover of the document and is dated January 2023.