The study was carry
out at a regional scale risk assessment to provide high level information on
coastal
hazards and the consequences of these hazards on key elements at risk. This is
to both provide an
understanding of the risks as they presently are expected and to provide a
baseline for comparing
alternative coastal management strategies.
The spatial extent of the study area is the open coast areas between Tangoio
and Clifton.
The hazards considered for this assessment are:
- Coastal inundation (overtopping and sea level rise) with 10%, 1% and 0.5%
Annual Exceedance
Probability (AEP) scenarios for the present day, 2065 and 2120. This
corresponds to a 10 year,
100 year and 200 year return period event.
- Tsunami (modelled by HBRC) for 3 m, 5 m and 10 m which, based on the GNS most
recent
tsunami modelling represents 0.5%, 0.13% and .025% Annual Exceedence
Probability (AEP) for
the present day coinciding with Mean High Water Springs (MHWS). This
corresponds to a 200
year, 750 year and 4000 year return period event.
- Coastal erosion (storm cut, trends, and effects of sea level rise) for 66%,
33%, 5% and 1%
likelihoods for the present day, 2065 and 2120.
For details refer to Tonkin and Taylor report: https://www.hbrc.govt.nz/assets/Document-Library/Reports/Coastal-Hazards/2016.SHAF.Risk-Assessment-Report.R5.pdf
Credits:
Tonkin and Taylor, HBRC, GNS
