Figure A2.3: Example probability-of-exceedance plot of predicted high water (HW) heights over the next 100 years for Queens Wharf (Wellington), excluding storm and global-warming effects
Return to the point in the document where this figure is located.
The traditional MHWS level in Wellington is 0.62 m, but it is exceeded by 46% of all high waters. A 'pragmatical' or the mean high water perigean-spring (MHWPS) level, which is 0.13 m higher than MHWS, is only exceeded by 11% of all high waters. The peak predicted tide height for the next 100 years is another 0.15 m above the 'pragmatical' MHWS.
Text description of figure
A probability-of-exceedance plot indicates the likelihood of a predicted high water level being exceeded. An example for Queens Wharf, Wellington Harbour, shows probability-of-exceedance for the next 100 years, excluding storm and global warming effects.
The highest tide would reach 0.9 metres above the mean sea level datum. This level would be exceeded by about only 0.002% of all high waters. By comparison, a traditional mean high water spring level of 0.62 metres would be exceeded by 46% of all high waters.
A "pragmatical" mean high water spring level, which is 0.13 metres higher than mean high water spring, would be exceeded by only 11% of high waters.
