Sand cover best for many years

16:00, Mar 22 2013

The hazy days of a long and golden summer have doubly-rewarded beachgoers with well-covered sandy beaches.

Beaches as far as the eye can see along the New Plymouth shoreline are looking their best for many years.

There have been times when the shoreline has been an unpleasant spot for swimmers as they struggled across metres of exposed pebbles and stones to get to the sea.

Not so this year.

New Plymouth-based oceanographer Peter McComb says he well recalls growing up as a Fitzroy kid in the 1970s when the denuded beaches were covered in stones.

"It was pretty grim."


However this year the settled weather has created a beach building phase, he says. "It tends to create a robust sedimentary environment on the beach."

While there is always the same volume of sand along the shore, it is distributed in different ways.

"Once you get strong wave conditions it tends to redistribute it across the surf zone."

While a massive "sand slug" is known to be gradually moving northwards along the coast after being sluiced down the Stony River during heavy rainstorms, this would be unlikely to be the reason for this year's sandy beaches, he says.

And any sand moving northwards would struggle to get past Port Taranaki, Mr McComb says.

"My interpretation of the healthy state of the beaches is more good weather than any injection of sand from the Stony River," he says. "The sand has to get past the port. It has a harbour entrance to cross. The only way is for a very large storm to transport the sand up the coast."

The sand slug also has a vast amount of storage at Back Beach and the Sugar Loaf Is before it reached the city beaches, he says.

"It could be as much as a decade before it reaches New Plymouth," Mr McComb says.

Port Taranaki harbourmaster John Ireland says he has found the beaches are so sandy this year he has struggled to find any rocks to throw for his rock-fetching dog.

"Quite often there are stones there but at the moment it's remarkably hard to find them."

He too believes the sand is a natural phenomenon caused by the benign conditions rather than a result of the port's dredge dumping sand along the shore.

The dredge regularly released 1000 tonnes of sand taken from the inner harbour. If the sand was a a "bit suspect" the decision was made to drop it offshore to minimise the potential effect on the beach. But if it was clean it is released inshore.

The message is to enjoy the sand while it's there. Mr Ireland says the rocks are only buried under one metre of sand and anticipates they are likely to be uncovered in the next storm.

Taranaki Daily News