What is flooding?

    There are several types of flooding.  The most common type of flooding in Bundeena occurs following heavy rainfall when rising water in Bundeena Creek overtops the creek banks and inundates surrounding land.  The upper parts of Bundeena are at risk of overland flooding when excess stormwater runoff flows overland towards Bundeena Creek or Port Hacking. Councils follow a floodplain risk management process that involves studying flood behaviour, and identifying and implementing measures to reduce flood risk. 

    When does flooding occur?

    Flooding is unpredictable and can happen at any time.  It can be many years between floods but multiple floods can happen in one year.  The size of a flood depends primarily on the intensity and duration of the rainfall that falls within a catchment during a storm. 

    Has flooding occurred in Bundeena?

    Flooding has occurred in Bundeena in 1969, 1977, 1984, 2012 and 2016.  These are considered to be minor floods. 

    Why can’t flooding be prevented?

    Flooding is a natural phenomenon that will always occur.  Problems with flooding arise when development occurs in floodplains that does not take full account of flooding.  Flooding can rarely be prevented but the risk to life and property posed by flooding can be managed. 

    Why is Council studying flooding?

    Floods represent a significant risk to life and can cause extensive damage, as recent floods across Australia have shown.  Under the NSW Government’s Flood Prone Land Policy, local councils have primary responsibility to manage flood risk. 

    What is my risk of flooding?

    Flood risk is a combination of the probability of a flood occurring and the impacts of that flood.  Flood risk maps show whether properties in Bundeena have a high, medium or low flood risk. 

    Generally, the lower the land and/or the closer to Bundeena Creek or overland flow path, the greater the flood risk. 

    What is a Floodplain Risk Management Study and Plan

    A floodplain risk management study and plan is a document that identifies, assesses and recommends cost-effective measures to reduce flood risk.  Measures to alter flood behaviour, modify property or change people’s response to flooding are discussed in the plan. 

    The Bundeena Creek Floodplain Risk Management Study & Plan was prepared as part of Council’s ongoing floodplain management program.

    What is the 1% flood?

    The 1% annual exceedance probability (AEP) flood represents a flood that has a 1% chance of occurring in any one year.  This is a rare but major flood. 

    The 1% AEP flood is used as a basis for defining the medium flood risk precinct and for setting flood-related development controls. 

    What is the probable maximum flood?

    The probable maximum flood (PMF) is the largest flood that could possibly occur.  Although it is an extremely rare flood, a small number of floods in Australia have approached the magnitude of the PMF.

    The PMF defines the maximum extent of the floodplain.  The area between the 1% AEP flood extent and the PMF extent is defined as the low flood risk precinct. 

    Why is Council talking to the community about flooding?

    The involvement of the local community is critical to successfully managing flood risk.  This involvement is ongoing through the preparation and later implementation of the Bundeena Creek Floodplain Risk Management Study & Plan.

    Council received valuable feedback from the Bundeena community in January 2018 regarding measures to reduce flood risk.  Council is now seeking further feedback on the draft plan and the recommended floodplain risk management measures. 

    Will flood information affect property values or insurance premiums?

    Council cannot advise on the implications of flooding on property values or insurance premiums.  Generally, however, property values are based on a range of factors of which flooding is only one.  Further information on flood insurance is available from www.floods.org.au/site/flood-insurance-fact-sheets.