Council looks north to shore up Kohimarama beach

By CATHY ARONSON

Mountains of white sand from northern east coast beaches may save another Auckland beach and its crumbling seawalls.

The Auckland City Council is considering topping up Kohimarama Beach with about 60,000 cubic metres of sand from the seabed near Pakiri or Mangawhai, as it did for Mission Bay in 1997.

This would give the beach up to 20m of sand between the water and seawall at high tide, compared with no beach at present.

Kohimarama Beach has been losing sand since the 1930s as more intensive development and stormwater drains have sent the sand out to sea.

The level of sand has now dropped below the seawall. The wall stops the waves from eroding the neighbouring road. But in 1994 the waves went under the wall and eroded the filling keeping it up.

The council made temporary repairs using rocks but the Auckland Regional Council has given it until 2005 to build a permanent replacement.

Auckland City is due to decide whether it will spend $350,000 on engineering reports to investigate spending $6 million on sand instead of $3.6 million to repair the seawall.

Recreation committee chairman Scott Milne said the sand was a better long-term option. It would stop the sea from reaching the wall and would give residents a recreational area.

The same technique was used on Mission Bay in 1997. It increased the area of dry sand available for recreational use from less than 3000 sq m to 14,000 sq m.

Council road services manager Neil Forgie said Mission Bay had lost minimal sand in the past five years.

The contract for Kohimarama Beach would include a provision that 90 per cent of the sand remained on the beach for 50 years.

Engineers were investigating ways of doing this, including building reefs that collect sand.

Mr Forgie said the extra sand would come from the seabed off the northern beach.

But the council has to wait for the result of an Environment Court appeal against Kaipara Excavators, who want to dredge two million cu m of sand from the seabed in the outer Hauraki Gulf.

The dredge will go as far north as Mangawhai, to within 2km of Little Barrier Island and within 3km of a marine reserve.

Pakiri Beach landowner Greg Macdonald is appealing on environmental and cultural grounds against the regional council's approval for the dredging.

Mr Macdonald said he was worried the consent placed no restrictions on the amount of sand taken in one year.

The city council is to make a decision this year on whether it will use the sand.

nzherald.co.nz/marine