2021-11-15 GC Agenda - Item 7 - Attachment 1 - Coastal Hazards Adaptation Plan

                                                                              Noosa Coastal Hazards Adaptation Plan




                                          Reference Box #2
                                                   Reference Box #2
                               Understanding ‘hazard’ and ‘risk’
                                        Understanding ‘hazard’ and ‘risk’
The risk from a natural hazard is determined by combining an understanding of the nature of
the
  Thehazard,
      risk fromhow  likelyhazard
                a natural  it is toisoccur, and what
                                      determined by thethe consequences
                                                        combined          might
                                                                 understanding    be nature
                                                                               of the if it didofoccur.
                                                                                                  the hazard,
Ahow   likelyisitais natural
   hazard            to occur,or
                               and what the consequences
                                 man-made                   if it did
                                               event that has      theoccur mightto
                                                                       potential   be.cause impacts to human
and ecological systems. This can include people, buildings, values, infrastructure, agriculture,
  A hazard is a natural or man‐made event that has the potential to cause impacts to people, buildings,
environmental         assets andenvironmental
  infrastructure, agriculture,      communities.     Hazard
                                                  assets       modelling helps
                                                         and communities.     Hazardusmodelling
                                                                                        understand
                                                                                                helpsaushazard’s
intensity   (or   magnitude),     frequency    and   source.  It  is typically  underpinned    by
  understand a hazard's intensity (or magnitude), frequency and source. It is typically underpinnedmathematical
                                                                                                              by
formulas    that describe
  mathematical       models thatthe propagation
                                  describe          of the hazard
                                           the propagation            acrossacross
                                                            of the hazard      the landscape.    InWe
                                                                                    the landscape.   most
                                                                                                        usecases,
  historical data
historical    data andandother
                           otherinformation
                                  informationin aare
                                                  mathematical   model to
                                                      also combined      in estimate  the probability
                                                                            the mathematical     modelof the
                                                                                                           to hazard
                                                                                                              estimate
  event  occurring.
the probability of the hazard event occurring.
Understanding
  Understanding the theimpacts
                         impacts     of the
                                 of the      event
                                         event  reliesrelies  on determining
                                                        on determining               the ‘exposure’
                                                                          the ‘exposure’               – that
                                                                                            – that is what     is, what
                                                                                                            things  will
things
  the hazard interact with (e.g. people, buildings, infrastructure, habitat etc.); and how the level of as
        the  hazard     will interact   with (e.g.   people,    buildings,    infrastructure,    habitat    etc.);
well  as the level
  ‘vulnerability’     of ‘vulnerability’
                  of each  – that is, how of
                                           willeach
                                                it cope– when
                                                          that is,
                                                                it ishow  will ittocope
                                                                      exposed             when itFor
                                                                                    that hazard?   is the
                                                                                                      exposed
                                                                                                           purposesto that
                                                                                                                      of
  the CHAP,
hazard?      fivethe
           For     difference
                      purposes criteria were
                                   of the     used to
                                           CHAP,         determine
                                                      five  differencethe possible    consequences
                                                                          criteria were     used toindetermine
                                                                                                        line with the
  Council’sconsequences
possible    risk managementinguidelines.
                                   line with These     were:risk management guidelines. These were:
                                               Council’s
•        Community
           Community –     Social
                         – Social
•        Community
           Community –     Economic
                         – Economic
•         Environmental
         Environmental
•        Council
           Council –– Financial
                      Financial
•         Council  –  Other
         Council – Other
The ‘risk’ to an asset/value is determined by combining the likelihood of the event occurring
   The ‘risk’ to an asset/value is worked out by combining the likelihood of the event occurring (in this case,
(ina coastal
     this case,    a coastal
              hazard           hazard event),
                      event), combined   with thecombined     with the expected
                                                   expected consequence     (impacts)consequence
                                                                                       of the event on(impacts)
                                                                                                       that
ofparticular
    the event     on  that particular   asset/value   (e.g. infrastructure     asset,  recreational  facility, etc).
               asset/value (e.g. infrastructure asset, recreational facility, etc). Table 1 shows an example   of
Table   1 shows
   how risk          an example
             is calculated          of how and
                           using likelihood  riskconsequence.
                                                  is calculated using likelihood and consequence.

     LIKELIHOOD                CONSEQUENCE

                               Insignificant     Minor             Moderate           Major             Catastrophic

     Almost Certain            Low               Medium            High               Very High         Very High

     Likely                    Low               Medium            High               High              Very High

     Possible                  Low               Medium            Medium             High              Very High

     Unlikely                  Low               Low               Medium             High              Very High

     Rare                      Low               Low               Low                Medium            High

                                                  Table 1: Calculating risk
                                              Table 1 - Calculating risk
    Estimating risk is has always been an uncertain science as it involves forecasting events for which the
 exact time and
Estimating  risklocation
                 requiresmight be largely unknown,
                            consideration            but is still
                                             of uncertainty   ascritical for making
                                                                  it involves       sure decisions
                                                                               forecasting   eventsarefor
 appropriately informed  by best available information.
which the exact time and location might not be known, but is still critical for ensuring decisions
are appropriately informed by the best information available at the time.

Noosa Council – Coastal Hazards Adaptation Plan                                                                   Page 23
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