Eating the shore: New Zealand's shrinking coastline
28 May, 2016
Erosion is eating away at New Zealand's coastline, with satellite images showing the dramatic impact of its appetite on small communities the length of the country.
It has forced people from their homes, and caused councils to relocate public infrastructure away from the encroaching sea.
But the issue is a contentious one, as shown on Thursday, when the Christchurch City Council announced the team of five experts comprising the second peer review panel to assess Tonkin and Taylor's Coastal Hazard Assessment Report. The move came after skepticism of the science behind the report, which identified 6000 properties that could be susceptible to erosion and nearly 18,000 at risk of coastal inundation over the next 50 to 100 years.
In the small West Coast town of Granity, the school has been engaged in a long battle with the sea, which it looks unlikely to win.
Coastal erosion claimed the school's pool when rocks were flung into it by a high tide, cracking the base. It is now bearing down on the playcentre, which is not currently at risk but will almost certainly be in the future.
Coastal erosion around the country has forced people from their homes, and caused councils to relocate public infrastructure away from the encroaching sea.
IAIN MCGREGOR/FAIRFAX NZ
Beach Road near Oamaru fell into the sea after years of coastal erosion.
Coastal erosion is a natural process which affects sand beaches and areas with soft cliff, and is caused by waves, tidal currents and wind wearing away the land. The sand and gravel stripped away is then deposited on other beaches through ocean currents, which is known as accretion.
Some beaches alternate between erosion and accretion, but cliffs can only erode.
Parliamentary commissioner for the environment Dr Jan Wright, who last year produced a report on the impact of sea-level rise, said the rate of coastal erosion would almost certainly increase.
"Where you have soft cliff, the result is very predictable – it can only go one way so erosion will go on at an accelerating rate.