Our Coast hazard assessment report - frequently asked questions
Why was the project done?
All around Australia governments, coastal councils and management agencies are working to build knowledge and understanding of the impacts of climate change on our coast. The Geelong-Queenscliff Coastal Mapping Project is one of four pilot local coastal hazard assessments across Victoria. These provide data and information to assist local communities and authorities plan for, and understand, the effects of climate change until the end of the century. The data and information will inform development of integrated management responses, planning, infrastructure upgrades and other work. It will also be used to inform the development of future climate adaptation plans.
How does it fit in with current state policy?
The scenarios used in the assessment report are consistent with the current Victorian planning benchmarks, to plan for sea level rise of not less than 0.2m by 2040 for urban infill areas and 0.8 by 2100.
What are coastal hazards?
The Victorian Coastal Hazard Guide, developed by the Department of Environment, Land, Water and Planning (DELWP), states that:
“Coastal hazards such as erosion and inundation are largely the result of the natural processes that occur along Victoria’s dynamic coastline. The high social, economic and environmental value that we place on our coastline means that the hazards produced by these processes affect Victorians beyond those just living and working on the coast. However, the processes are highly complex and heir effects are difficult to predict with any certainty.” Climate change is expected to exacerbate and accelerate these processes.
What is coastal inundation and how is it different from catchment flooding?
In summary, coastal inundation is driven by tides and waves from the sea forcing ocean water onto low-lying coastal land. Riverine flooding on the other hand is caused by rain falling within a water catchment, then flooding low-lying land. One of the most important differences between coastal inundation and riverine flooding is their duration. Riverine flooding may last for many hours, even days or weeks. Coastal inundation on the other hand is influenced by the combination of tides and storms. A high tide occurs approximately every 12 hours in Victoria. The duration of inundation is thus controlled by the duration of the peak of the high tide. The level, extent, period and impact of inundation will have significant effects on the coast as sea level rise above existing levels.
How will the coastal hazards assessment report information be used?
The hazard assessment report provides local authorities and communities with new data based on the best available science. The mapping and information will be used as an engagement tool to better understand community values, issues and priorities for collaborative action on climate change.
This will help communities make informed decisions about living along and around a dynamic and changing coastline. It will allow management agencies and other stakeholders to identify and define triggers as the basis for short, medium and long-term management responses.
Where can I read the full assessment report?
Copies of the full report and summary report are available on the Our Coast website at www.ourcoast.org.au
Inundation maps for the areas around Edwards Point, St Leonards township, the Salt Lagoon precinct, Indented Head township and the Esplanade between Portarlington and Indented Head are also provided. A map is also provided for Portarlington township which also includes the area around Point Richards.
Why does the Local Coastal Hazard Assessment, the website and the Our Coast program in general only deal with coastal inundation?
To confidently be able to model and map coastal hazards there is a need for accurate and adequate data on which to base such modelling. A lack of erosion data was highlighted by the consultants responsible for producing the Local Coastal Hazard Assessment and reinforced when the report was peer reviewed. It was identified that further information would be needed to enable high levels of confidence for modelling and mapping erosion hazards in such a dynamic environment. As the Our Coast program progresses, and more data becomes available the hazard presented by erosion will be reassessed.