Vanessa Reid: Sand mined from Pakiri irreplaceable


Auckland City's recreation committee chairman, Scott Milne, says a $5 million beach rebuilding plan is gathering momentum. Where, however, does he hope to source the sand for the next eight Auckland beaches requiring replenishment?

Yes, the Pakiri-Mangawhai embayment is the nearest, and hence the most economical, area that the sand can be brought from to replenish Auckland's inner-city beaches. But when the Kohimarama replenishment is complete, no more sand should be taken from the Pakiri area.

I am not opposed to the idea of replenishing beaches with sand for the public's good. Let's make Auckland look more attractive - but not to the detriment of the Pakiri and Mangawhai Beaches. Let's ensure a variety of sand sources for beach replenishment are used.

There are simply too many demands being made on Pakiri-Mangawhai for it to be sustainable. This is an area that has had more than 30 years of inner-shore sand mining (0 to 25m water depth), totalling more than 2.3 million cu m, according to a 1998 study by the National Institute of Water and Atmospheric Research (Niwa).

As well, there have been occasional outer-shore extractions, such as that which supplied Mission Bay in 1995.

Furthermore, in 1998 (in a decision being contested in the High Court), the Auckland Regional Council and the Minister of Conservation approved a sand-mining company's application to mine two million cu m from the outer shore over the next 20 years. Other companies are free to apply for further extraction rights.

And to add insult to injury, the inner-shore sand-mining 10-year resource consents are up for renewal this year. They should be rejected by the regional council because of the visible erosion on Pakiri Beach, the loss of the near-shore bars and surfing breaks, and the dangerous nature of the beach because of the large number of severe rips and holes created by taking sand so near the shoreline.

The consent process is being held up because the sand-mining companies have failed to get adequate information to the regional council for their applications to be notified to the public.

On these grounds alone, the regional council should dismiss their option to the sand because while indecision reigns, the inner-shore mining can (and, unsurprisingly, does) continue, even though February this year was the expiry date of the 10-year consent.

The Pakiri-Mangawhai embayment is a finite source of sand and is, therefore, a closed system. It was supplied by sediment when the Waikato River, on two occasions, came out at the Firth of Thames more than 20,000 years ago. Obviously this is no longer the case, so even at the outset it is an unsustainable source of sand. What is taken out will never be regained.

To quote from Niwa's 1998 Mangawhai-Pakiri sand study: "Sand extraction is not sustainable in a closed system in the long term because extraction will eventually deplete the resource to zero and/or cause beach erosion."

And let's also be upfront about who these sand-mining companies are.

They are not public benefactors working for our greater good; they are commercial entities, not friendly dredgers.

The main use of the sand is for mixing into concrete. The beach replenishment programmes are, by volume, small jobs for them and good visible public relations exercises. In fact, all groups concerned with any beach replenishments stand to make a lot of money.

For the sake of those who live in the Pakiri-Mangawhai area and those who holiday and visit there, let's not allow it to be destroyed because there are not enough people to complain loudly enough. Is this another reason they continue to mine there? You don't see dredging off Omaha any more.

A solution could be to look to the naturally replenishing, open-sand system of the west coast where, near the Kaipara Harbour, the sands are fine-grain and golden. It is well documented that there is a "river of sand" running up this coast.

We should start making the sand-mining companies move their sourcing and premises west. The east has had enough taken from it for the moment; it cannot sustain all these demands.

So Aucklanders who want to replenish Auckland's inner-city beaches in one to two years rather than 10 should think first of where this sand is to come from, and the disturbances to the delicate ecological systems of our dunelands and seabed when mining is done. Extreme caution in resource management planning is needed.

Secondly, should all eight beaches be replenished in less than 10 years, they must not be sourced entirely from the Pakiri-Mangawhai embayment simply because it is the easiest to get to and most economical.

Nor should the east coast-based sand-mining companies look towards Great Barrier Island.

It is viewed as an ideal conservation area, as demonstrated by the purchase of adjacent Kaikoura Island.

The magnificent white stretches of sand on Great Barrier's beaches are within the same closed system as the Pakiri-Mangawhai embayment (their sand is also derived from the ancient Waikato River mouth near Thames) and are, therefore, a finite resource.

We do, however, have the west coast, where the sand is a naturally replenishing resource.

The latest Kaipara sand study should be released as soon as possible for public consumption so prudent resource management planning for our sand resources can be initiated.

And, in line with this judicious planning, the inner-shore mining in the Pakiri-Mangawhai embayment should be halted once and for all.

* Vanessa Reid is an Auckland businesswoman whose family own land at Pakiri.

Herald Feature: Conservation and Environment

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