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.

    Pictures

    What's involved

    Stage 1: Gap Analysis

    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.

    Stage 2: Data Acquisition

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

    Stage 3: Coastal Hazard Assessment

    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.

    Stage 4: Capacity Building

    Integrating all the hazard data into decision support systems for the use of local and state governments, land managers and asset owners to help them make decisions and prepare for the future based on scientifically based information.

    Who's involved

    Commissioned by DELWP, the technical assessment will be 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.

    Project timeline

    Key milestones include:

    • Late 2017 – Initial project planning commenced
    • July 2018 – Commenced collection of existing data and understanding data gaps
    • Jan 2019 – CSIRO commenced the gap analysis – a synthesis of relevant existing information/ data and identification of any critical gaps required to complete the hazard assessment
    • July 2019 – Summary of key findings from the gap analysis
    • June 2021 – Hazard assessment completed
    Project outputs

    There will be a range of project outputs, they include:

    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   “helped council to be aware of any potential planning issues early on and to   provide planning information as needed”

    Planning related outcomes

    • Within two months   of the final report being released the hazard maps were being used at VCAT   and in developing structure plans and new flood controls
    • Planners can   consider it when making planning decisions and it has resulted in new   developments in hazard zones being required to provide a coastal assessment   for their property.

    Other outcomes

    • Additional   support has been leveraged from the state to build/reinforce protective   infrastructure – e.g. protective sea walls.
    • Community   members did post-project awareness raising about what the hazards were and   what they mean 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 CMA, providing   for better informed planning responses.
    • Other coastal   managers pointed to it as useful “for arguments that I make in relation to   some issues”.

    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:

    • identified that   groundwater is a key issue in some areas that was not able to be assessed as   part of the LCHA

    It’s a useful reference point. At least now we know what the data gap is – we can then focus in on how we can address that gap

    Western Port

    Integration into the planning scheme

    • Bass Coast   Shire Council has integrated the results of the LCHA into their planning   scheme and it is used to assess planning applications.

    Decision-making regarding council assets

    • Other councils   have not adjusted their planning schemes or similar, but have in select cases   used the information to make decisions on their own capital works.

    Gippsland

    General improvements in capacity

    • Awareness of it   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

    I think it’ll be enormously useful as a strategic decision-making tool … but not a site-by-site one.

    • Wellington Shire   have used it to expand the area in which they apply climate change plans on   property titles, which require landowners to plan responses to climate change

    source: Local Coastal Hazard Assessment Learnings Project (Gilmour and Healey 2017)

    Victorian coastal hazard assessments

    A state-wide assessment of erosion and inundation hazards resulting from future climate change scenarios was completed in 2017.

    Four pilot Local Coastal Hazard Assessments have been undertaken in Victoria

    Further information and resources

    Changes in Coastal Climate – National Environmental Science ProgramME

    Victorian Coastal Hazard Guide – Victorian Coastal Council

    Understanding coastal hazards to reduce impacts – National Environmental Science Programme

    Coastal Hazards: Preparing for the threats that face our coastal communities National Ocean Service (US)

    Page last updated: 12/01/21