Nothing special about today: 2.1 m tide; barometer 1010; moderate swell from the south. But look where the sea got to at high tide!
The NZ Govt document Coastal Hazards and Climate Change: A guidance manual for local government in New Zealand warns of the following impacts on New Zealand’s coastal areas due to accelerating sea-level rise:
- increased coastal erosion in some areas. Parts of the coastline that have historically been eroding may experience
- increased erosion trends; other areas that may have been relatively stable may begin to erode;
- permanent high-tide inundation of very low-lying margins that may at present experience only episodic inundation;
- episodic sea flooding of higher coastal and estuarine margins;
- drainage problems in adjacent low-lying areas, especially where gravity is relied on;
- increased rates and frequency of episodic wave run-up and overtopping of both natural and man-made coastal defences.
The manual continues by warning about the increased hazard created by the removal of coastal vegetation, and risks associated with storm surge, “where adverse winds and low barometric pressure produced by storms temporarily elevate the ocean level well above the predicted tide level” and wave run-up which is, “treated separately from storm-tide level because it varies widely along the coast, even in the same locality, due to differences in shoreline steepness and type of natural or artificial coastal barrier.”
People who frequent South Beach near Patiti Point will tell you that the wave patterns and the shoreline steepness change from day to day in this locality, and that it is an increasingly common occurrence for the waves to roll right up the beach and fill pools behind the main wall of shingle.
