Port Phillip Bay Coastal Hazard Assessment

Port Phillip Bay is the largest bay in Victoria, Australia. It is home to thousands of plant and animal species, and some 1.3 million people live along its coastline. The Bay and its coastline support a variety of activities, including water sports, recreation, commercial and recreational fishing, marine tourism, and shipping.

Like all coasts, Port Phillip Bay is vulnerable to coastal hazards. As sea levels rise, areas along the coast are likely to experience increased erosion, inundation, and groundwater change, which threaten the security of communities, assets and ecosystems. With climate change increasing the frequency and severity of hazards and hazard events, it is important that we understand what this means in the Bay area, so that we can plan for adverse impacts on coastal communities.

To do this, we are working with CSIRO to carry out a coastal hazard assessment for Port Phillip Bay. This assessment will look at the likely extent of inundation (flooding), groundwater change, and erosion for the Bay.

The Coastal Hazard Assessment will identify likely coastal hazard impacts around Port Phillip Bay through data analysis and modelling of a range of anticipated climate change scenarios. The data generated through the assessment will be shared with land managers and the community, to help them consider climate change in their future planning.

Decision Support System

Decision Support System tool for visualizing coastal hazards

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Coastal Hazards, three types are inundation, erosion, and groundwater

Diagram

Gathering and understanding existing information on coastal inundation, erosion and groundwater change for the Bay and identifying any critical gaps in data required to complete the hazard assessment.
Summary of the key findings of the Gap Analysis

Filling any critical data gaps by sourcing further data, or undertaking further research.

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Undertaking the hazard assessment by modelling future climate scenarios to define the extent of land around Port Phillip Bay expected to be threatened by inundation, shoreline and groundwater change.
Project Overview Fact sheet

Integrating all the hazard data into a Decision Support System for use by local and state governments, land managers and asset owners to plan for the future using scientifically based information.
Decision Support System Fact sheet

Publishing results from the Port Phillip Bay Coastal Hazard Assessment, including technical report, summary document, data upon finalisation and maps.

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Who's involved

Commissioned by DELWP, the technical assessment is being carried out by a team headed up by CSIRO, with support from Federation University, MetOceans Solutions and several consultants.

DELWP is also working closely with the 10 bay-area councils, Parks Victoria, Melbourne Water, two catchment management authorities, the Association of Bayside Municipalities and Traditional Owners.

Expected project outcomes

The expected outcomes of the hazard assessment include:

Identification of coastal hazards in the Bay and the extent of potential impact.
Inundation, erosion and groundwater data for the Bay.
Hazard mapping data for the Bay.
Stakeholders provided with the most up to date information to inform planning decisions and management of assets.

The table below summaries the uses of and outcomes from the four local hazard assessments completed in Victoria as examples of the types of outcomes expected from the Port Phillip Coastal Hazard Assessment.

LCHA Pilot	Use/ value/ other outcomes from the LCHA
Port Fairy	General improvements in capacity The LCHA has made council aware of any potential planning issues early on and to provided planning information as needed. Planning related outcomes Within two months of the final report being released, the hazard maps were in use by the Victorian Civil and Administrative Tribunal and being used to develop structure plans and new flood controls Planners can incorporate findings of the LCHA into their decision making. This has resulted in new developments in hazard zones requiring a coastal assessment. Other outcomes Additional support has been leveraged from the state to build and reinforce protective infrastructure – e.g. protective sea walls. Community members did post-project awareness raising about what the hazards were and the implications for the community. A community group has started beach monitoring at a key site of interest.
Bellarine	General improvements in capacity The inundation output was noted to be very useful for the Catchment Management Authority (CMA), providing for better informed planning responses. Other coastal managers used the findings to help define their position. Enabled further projects and work Real-time animation of the modelling with CSIRO. Funding through the Victorian Adaptation and Sustainability Partnership to support risk assessment and adaptation work. Highlighted further hazards and work needing to be completed, such as where the groundwater was a key issue. The findings provide a reference point to identify data gaps that can be addressed.
Western Port	Integration into the planning scheme Bass Coast Shire Council has integrated the results of the LCHA into their planning scheme, which is used to assess planning applications. Decision-making regarding council assets Where other councils have not adjusted their planning schemes or similar, used the information to make decisions on their own capital works.
Gippsland	General improvements in capacity Awareness of the LCHA findings among VicRoads, SES, local government, CMAs and consultants. As noted by one CMA interviewee: “We use them …Anyone doing long-term planning on the Gippsland Lakes should be aware of them”. Enabled further projects and work East Gippsland Shire are looking at doing an adaptation plan for Lakes Entrance with the LCHA as a key input. Planning related outcomes Data is currently being used in a VASP-funded project at Paynesville, as well as additional work for strategic planning related to infrastructure replacement. Wellington Shire has used it to expand the area in which it applies climate change plans on property titles that require landowners to plan responses to climate change.