Higher tides add to rising seas

King tides are due to hit the Auckland region just as experts discuss the impact of higher tides on sea level rise in New Zealand.

Graeme Blick, Land Information New Zealand’s Chief Geodesist, is presenting on the impact of tides as well as earth movement at the Sea Level Rise in New Zealand Conference. He says what are commonly called king tides are higher than usual tides caused by the alignment of the sun and moon.

“As we plan for rising sea levels, it’s vital to consider those times of year when the sea reaches a higher level on the coastline,” says Graeme.

“LINZ produces authoritative tide predictions for New Zealand. We see the highest astronomical tide once every 18 years and spring tides about twice a month in some parts of the country. In fact, the Auckland region will be seeing these over the next couple of days, with particularly high tides on Saturday and Sunday evening.”

Ground movement in specific regions is also a factor to consider says Graeme.

“New Zealand is never staying still. As well as the extremes we see during earthquakes, there are other more gradual movements caused by the movement of tectonic plates and the country is very slowly sinking or rising at different times and in different places.

“It’s too early to say what this will look like in the future, but LINZ is gathering more data on this to get a better picture of this movement over time. We’re also working to improve the information we have about elevation – the height of our land and features. This will be crucial for understanding how we can respond to rising seas and flooding.”

Spring tides predicted for the Auckland region over the weekend 9/10 April

8:40am – 3.64 metres
9:06pm – 3.67 metres

9:32am – 3.64 metres
9:57pm – 3.67 metres

These measurements are heights above the lowest tide.