‘Whole of dune’ restoration carried out
It’s just not the dynamics of the ocean that needs to be considered when dealing with coastal erosion — the dynamics of a community are equally as important.
Coastcare Waikato, a partnership between local communities, iwi, district councils and Waikato Regional Council to protect and restore the region’s coastlines, has this year undertaken its largest dune restoration project, along 700m of Whangamata¯ shoreline that was badly eroded by Cyclone Gabrielle.
The cyclone removed much of the dunes at the south end of the beach, increasing the exposure of 30-plus properties to future storms.
Neil Richardson, one of many homeowners anxious about the future of their coastal properties, says quick action was needed to address the exposure, and conflict would have been inevitable without agreement on a working plan to move forward.
“Conversations and compromises were needed right at the start,” Richardson said.
“All the usual questions arose. What should be done? Who is responsible for the work? Who pays? How will any work achieve the multiple goals of the residents, local and regional council, local iwi and other vested parties. How do we achieve a long-term solution for the whole beach, rather than just for individual properties?
“Happily, the experience has been an extremely positive one.”
Coastcare coordinator Andy Warneford, who works with communities between Tairua and Whiritoa, says the landowners approached Thames-coromandel District Council wanting a solution.
“Of course, they talked about sea walls, but we managed to steer them in the direction of giving a soft coastal method a chance to show what can
be done.”
Coastcare Waikato had already successfully restored a number of beaches in the Coromandel Peninsula with a soft engineering method known as a ‘whole of dune approach’, for example, at Ku¯aotunu, Tairua, Greys Beach and Cooks Beach.
“People were understandably pretty stressed out. That is the Pacific Ocean there 20 metres away from their home and they have a towering escarpment right on the boundary of their property.”
The whole of dune approach involves spraying and removing remaining exotic vegetation along the top of a dune, burying it, and reshaping the dune to the correct gradient using earthmoving equipment and beach sand. The newly created dunes are then planted with
native ko¯whangatara/spinifex and p¯ıngao to trap the sand and allow them to naturally rebuild after storm events.
“Usually, a 200m restoration project is considered quite chunky,” said Warneford. “But in Whangamata¯, we did 750m of almost continuous restoration in front of about 40 houses.
“Sand dunes give protection to the land behind them; they act as a buffer against eroding wave action.
“The dunes at Whangamata¯ fluctuate dynamically landward to seaward, however, the recent years of La Nina have meant the dunes in some places are at their most landward since 1944.
“By doing dune restoration, we create more sand for storms to take away — instead of land or infrastructure.”