Sea level rise is an issue that is receiving spirited debate across all levels of the community, government and also the scientific community. Council does not have the expertise to analyse the complex issues associated with sea level rise and relies on State and Federal Governments to provide professional investigation, advice and direction on the projected sea level rise increases to assist in land use planning.
The NSW State Government released the NSW Sea Level Rise Policy Statement in October 2009. This document states “The best national and international projections of sea level rise along the NSW coast are for 40 cm by 2050 and 90 cm by 2100”. Figures stated in the NSW Sea Level Rise Policy Statement are based on the best available scientific and specialist information and as such Council has adopted the planning level for sea level rise of 0.9m by the year 2100.
While the NSW Sea Level Rise Policy Statement has not to date changed, the State Government has initiated a review. Council has been informed that the terms under which the review is being undertaken are as follows: “Current sea level rise benchmarks used to guide land use planning and infrastructure design in NSW are based on advice from both the Intergovernmental Panel on Climate Change (IPCC) and CSIRO. The NSW Government is committed to regularly reviewing these benchmarks to ensure that they are based on the most appropriate science.”
The O’Farrell Government is concerned about the impacts of projected sea level rise on coastal erosion and flooding in coastal areas. To address these issues, a Ministerial Taskforce has been established to ensure that NSW has the best plans, legislation and other arrangements in place to deal with coastal risk. Establishing this Taskforce is an important step in ensuring that NSW has the best arrangements in place to manage coastal erosion and other coastal hazards, both now and into the future. The Taskforce will also review the application of sea level rise planning benchmarks and the adequacy of the science informing these benchmarks and will report to the NSW Cabinet.
Council is responsible for planning for future development in Gosford, for managing the natural environment and for the wellbeing of current and future residents. Planning and development decisions taken now will be “on the ground” in 50 to 100 years. This places a duty of care on Council to plan for the future based on the best available information.
The adopted rate for sea level rise allows Councillors, Council staff and the community to assess the potential risks associated with projected rise in sea level. It also enables Council to develop policies, carry out more detailed studies and make planning and development decisions that are suitable for the changing conditions.
Gosford City Council recognises that sea level rise is a global problem that will impact locally on the NSW coastline and will require action by all levels of Government, including Council, and also the community. As a result, Council would like to ensure the community is informed of Council’s current sea level rise policy and related strategies, and what they mean for property owners. The following webpage outlines the potential impacts of sea level rise, state government policy, Council’s planning level & current strategic planning, and information for property owners.
Vulnerability of the Gosford Local Government Area to Sea Level Rise
Rising sea levels will bring significant change to Australia’s coastal zone in the coming decades. Many coastal environments such as estuaries, beaches, low lying floodplains, lagoons and wetlands are closely linked to sea level. There is a lack of knowledge in many cases as to how these environments will respond to sea level rise but the risk of tidal inundation / flooding of low lying areas and the potential beach loss must be considered in the Council decision making.
The Australian Government’s Department of Climate Change released the report entitled
Climate Change Risks to Australia’s Coast – A First Pass National Assessment, that brings together existing and new information to highlight the scale of the problem that Australia faces as a vulnerable coastal nation. The assessment provides an analysis of residential property at risk from inundation and erosion around the Australia coastline at the end of this century. This report identifies the Gosford Local Government Area as the third most vulnerable area in NSW to sea level rise.
There are approximately 90kms of Brisbane Water foreshore, 50kms of Hawkesbury River foreshore, 14kms of beaches, 4 major coastal lagoons and numerous smaller waterways within the Gosford Local Government Area which are potentially affected by sea level rise.
Due to the extensive length of foreshore, planning for sea level rise is and will be over the coming years very challenging and demanding for Council.
Current Scientific Knowledge and Projections of Climate Change
Australia’s two leading climate science agencies – the CSIRO and Bureau of Meteorology – have recently produced snapshot of the state of the climate to update Australians about how their climate has changed and what it means.
The snapshot is sourced from peer reviewed data on temperature, rainfall, sea level, ocean acidification, and carbon dioxide and methane levels in the atmosphere. From this review, the CSIRO/BOM determined the following:
- the rate of sea level rise increased during the 20th century,
- sea surface temperatures around Australia have increased in the past 50 years,
- trend over five decades of rainfall decreasing across much of southern and eastern Australia,
- that all of Australia has experienced warming over the past 50 years,
- the number of days with record hot temperatures has increased each decade over the past 50 years,
- there have been fewer record cold days each decade.
The key findings from the report are:
- Australia will be hotter in coming decades
- Much of Australia will be drier in coming decades
- Climate change is real
What Potential Impacts will Sea Level Rise have on Coastal and Foreshore Areas of Gosford?
Recent experiences internationally have shown that in a changing climate, sea level rise is a real and growing threat to the present-day sustainability of our coasts and foreshore areas. Sea level rise is predicted to have significant impacts upon coastal areas. Some of the predicted future impacts of sea level rise include:
- Increase in the areas affected by permanent tidal inundation
- Increase in the intensity of regular and extreme tidal inundation/flood events. The Australian Government’s Department of Climate Change projects that with a mid-range sea level rise of 0.5 metres, inundation events that happen now every 10 years would happen about every 10 days
- Increase in the risk of beach and dune erosion. Shoreline retreat can be 50 – 200 times the vertical sea level rise, depending on coastal geomorphology;
- Changes to the coastal ecology and ecosystems. Terrestrial and aquatic plants and animals that rely on coastal habitats are likely to be adversely affected
- Risk to built environment assets which could have consequences for the delivery of community and essential services
Current State Government Policy & Guidelines with Respect to Sea Level Rise
In October 2009, the NSW Government released the NSW Sea Level Rise Policy Statement to support adaptation to projected sea level rise impacts. The Policy Statement provides the following Sea Level Rise Planning Benchmarks for use in assessing the potential impacts of sea level rise in NSW:
- increase of 0.4m by 2050 (relative to 1990 mean sea level)
- increase of 0.9m by 2100 (relative to 1990 mean sea level)
The SLR planning benchmarks can be used for purposes such as:
- incorporating the projected impacts of sea level rise on predicted flood risks and coastal hazards;
- designing and upgrading of public and private assets in low-lying coastal areas where appropriate, taking into account the design life of the asset and the projected sea level rise over this period;
- assessing the influence of sea level rise on new development considering the impact of sea level rise on coastal and estuarine habitats and culturally significant sites and identifying areas at most risk from sea level rise,
- assessing the impact of changed salinity levels in estuaries, including implications for access to fresh water.
The primary purpose of the benchmarks is to provide guidance supporting consistent considerations of sea level rise impacts, within applicable decision-making frameworks. This includes strategic planning and development assessment under the Environmental Planning & Assessment Act 1979, along with infrastructure planning and renewal.
The use of these benchmarks is required when undertaking coastal and flood hazard assessments and studies in accordance with the NSW Coastline Management and Floodplain Development Manuals. It is already a statutory requirement that the preparation of Local Environmental Plans gives effect to and must be consistent with these manuals.
For more information about how these sea level rise planning benchmarks have been determined, refer to the Technical Note: Derivation of the NSW Government’s Sea Level Planning Benchmarks
In addition in October 2009, the above NSW Department of Planning released the Draft NSW Coastal Planning Guideline: Adapting to Sea Level Rise to provide guidance on how sea level rise and its associated impacts are to be considered in land use planning and development assessment in coastal NSW.
In conjunction with the release of the Department of Planning draft Guideline, the Department of Environment, Climate Change and Water (DECCW) have prepared the following two draft guidelines to assist Councils incorporate the sea level rise planning benchmarks in coastal hazard studies and flood studies:
- Draft Coastal Risk Management Guide: Incorporating the sea level rise benchmarks in coastal hazard assessments
- Draft Flood Risk Management Guide: Incorporating the sea level rise benchmarks in flood risk assessments which should be read in conjunction with the
- 2007 DECC Floodplain Risk Management Guideline: Practical Consideration of Climate Change
Gosford Council’s current adopted Sea Level Rise Planning Level
In recognition of the State Government policies/guidelines and Council’s duty of care in respect to future planning in the Gosford local government area, Council placed the sea level rise planning level of 0.9m on public exhibition between 12 August 2009 and 18 September 2009.
The public exhibition included the publication of sea level rise maps that were produced to provide an initial indication of areas that may be potentially impacted by increases in sea level of up to 90cm above various scenarios as listed below:
- average tidal inundation
- king tide inundation
- 1% Annual Exceedence Probability (AEP) flood inundation
- Ocean storm surge inundation
The purpose of the consultation activities was to exhibit and inform the public. Council was seeking to share information about sea level rise so the public would gain knowledge and become acquainted with the facts as they were understood by Council at the time. The consideration of a planning level for sea level rise and the exhibition of sea level rise mapping was an initial step that will assist this Council to work with its community through this complex and multi-faceted problem.
Following the public exhibition, Council reviewed the submissions and at the meeting held on the 1st December 2009, Council resolved the following:
- Council adopt 0.9m as its sea level rise planning level for the year 2100 with an assumed linear increase from 1990 levels as the basis for Council staff to proceed with risk assessment, policy development, and strategic planning decisions.
- The sea level rise planning level is used in all relevant strategic processes and Council commit to reviewing all relevant strategic documents to incorporate the adopted sea level rise planning level to enable management options for development controls to be developed.
- The sea level rise planning level is used in all relevant asset management and capital works project planning processes to enable proper consideration of potential sea level impacts in all relevant decisions.
- A notation be placed on planning certificates pursuant to s149(5) of the Environmental Planning & Assessment Act 1979 that the land is within the 0.9m sea level rise extent as identified on the most relevant map held by Council.
- The sea level rise planning level be reviewed upon the adoption of new information or policy by State Government and the process of this review involve engagement activities with the community.
- The measures already in place to address coastal risk and flood risk continue to be applied and are reviewed upon the adoption of new information or policy by State Government.
- Council write to the Director General of the Department of Planning requesting the formulation of a Severe Physical Hazard zone for inclusion in the standard template.
In response to Resolution D, Council identified all the properties found to be affected by projected Sea Level Rise up to 0.9m above the 1% estuary and storm surge flood events. In 2010 a s149 (5) Planning Certificate message was then applied to each of these identified properties and a letter sent to each property owner advising of Council’s resolution and the application of the encoding. However due to the lack of consistency and clear direction from the State Government Council at its meeting held on the 3rd July 2012, resolved that:
- Council remove the S.149(5) Planning Certificate message that relates to sea level rise until such time as the NSW State Government Legislate/Regulates that all Local Government Councils in NSW give a clear direction to all property owners who are affected by this event.
- Council write to our Local State Members seeking their support in the State Government providing a clear direction on a consistent approach across the state regarding sea level rise and s149 (5) Planning Certificate messages or that they repeal the Legislation.
In accordance with resolution A Council in July 2012 then removed all the s149 (5) planning certificate messages relating to sea level rise from each of the previously identified properties.
In accordance with resolution B letters were sent to Local State members of parliament seeking their support in the State Government providing a clear direction on a consistent approach across the state regarding sea level rise and s149 (5) Planning Certificate messages or that they repeal the Legislation.
At the meeting held on the 4 September 2012, Council resolved the following:
- That sea level rise mapping on Council’s website be presented in a single series of maps across vulnerable areas based on king tide levels and 20cm, 55cm and 90cm increments.
In accordance with resolution B the sea level rise mapping has now been simplified to one map only.
Identification of Properties Potentially Affected by Sea Level Rise
The adoption of a sea level rise planning level has the possibility of affecting the future use and development potential of certain land in the vicinity of the coast and estuaries. Until specific strategic plans that relate to an area have been completed (such as floodplain, coastal and estuary risk management studies) it is currently difficult to determine with certainty what specific mitigation/development controls can be applied to affected land within the area.
Gosford Council’s Current Strategic Planning and Actions in relation to Sea Level Rise
Planning for an uncertain future, where the trends of the past cannot be relied upon, is an emerging issue for Council. In undertaking this complex planning, Council will be, in many instances, “breaking new ground”.
Planning for sea level rise and more broadly climate change is, and will be over the coming years, very challenging and demanding for Council. This Council has a relatively strong tradition in planning for hazards such as coastal erosion and flooding through the development of coastal management plans, estuary management plans and floodplain risk management plans. These have provided our community with information and guidance regarding local flooding and coastal erosion issues that already exist. In many cases these plans have accurately predicted hazards and subsequently have alleviated risk to life and damage to property.
As the changes to climate manifest themselves over time, it is likely the extent of hazards such as these will change, and this planning tradition will assist with meeting the challenges we will face. To enable this to happen it is important that climate change parameters such as a sea level rise planning level be adopted to ensure it is imbedded into these strategic processes.
It is equally important that a sea level rise planning level is a consideration in all asset management and capital works project planning.
The process for doing this is best described in the flowchart below:
Our Sea Level Planning Process
Figure 1 – the sea level planning process
Public participation in deciding on how the impacts from sea level rise are to be managed will follow at a later stage, when strategies are being developed. Council is currently undertaking the following strategic plans that could potentially determine development controls and strategies for particulars areas:
- Brisbane Water Foreshore Floodplain Risk Management Plan
- Erina Creek Floodplain Risk Management Plans
- Narara Creek Floodplain Risk Management Plans
- Gosford Open Coast and Broken Bay beaches coastal processes and hazard re-assessment.
- Coastal Lagoons Management Studies
- Brisbane Water Estuary Management Plan
- Lower Hawkesbury Estuary Management Plan
As further resources become available further strategic plans will be undertaken on other areas potentially affected by sea level rise.
Local residents are encouraged to become involved with these studies via community consultation forums such as public meetings, workshops, community surveys and other initiatives. The community consultation forums will be advertised in the local papers and on Council’s website.
Forums will provide residents the opportunity to have their say and help shape the adaptation management options that could include development controls and engineered structural controls.
Engagement with community networks and interested groups will be essential as this Council adapts and responds with the aim of becoming more resilient to the impacts of climate change. This will be an ongoing process and as new information from State Agencies is received by Council, it will continue to be shared with the community.
View the following resources for further information:
- NSW Department of Environment & Heritage – Sea level Rise
- NSW Department of Environment & Heritage – Coastal Reforms
- Commonwealth Department of Climate Change
- NSW Department of Planning – High resolution terrain mapping of the NSW Central and Hunter coasts for assessments of potential climate change impacts