'Simple maintenance' could save Aramoana groynes, group says

Inspecting the groynes at the harbour end of the spit by Aramoana are (from left) Aramoana League...
Inspecting the groynes at the harbour end of the spit by Aramoana are (from left) Aramoana League committee member and former secretary John Davis, president Bill Brown and vice-president Paul Munro. PHOTO: SIMON HENDERSON
For the past 30-odd years the Aramoana League has been highlighting the deteriorating state of a series of groynes at the end of the mole at Aramoana.

Now the group hopes a meeting in June between the league and Otago Regional Council, Port Otago and the Department of Conservation may help highlight its desire that the long decay of the groynes be reversed.

Vice-president Paul Munro said the history of the groynes started with construction of the mole in 1885, designed to stabilise the depth of a harbour channel to enable safe passage for ships.

Over time sand built up in the area created by the mole, now called Shelly Beach and marram grass was planted to fix the sand.

The Long Mac, a secondary groyne, and three sub groynes, were created with rock ferried from the other side of the harbour.

This helped guide flood and ebb tidal currents so sediment did not build up in the harbour channel.

Mr Munro said for many years the groynes proved effective.

"Even as early as 1906 it had worked so well that they built the pilots’ houses on the end here."

But over time they were no longer being maintained, and the effectiveness of the groynes began to dissipate.

Mr Munro said the issue had been investigated by Port Otago over the years, including a July 1998 report by environmental authorities Martin Single and Prof Wayne Stephenson.

This report highlighted having a stable sand dune barrier at the entrance to the harbour provided some protection against tsunamis.

Mr Munro said it hoped a collaborative approach would help protect the area.

"This was created by humans and could be saved by humans by simple maintenance," Mr Munro said.

The Aramoana League had opened up talks with the Otago Regional Council and Port Otago and hoped to gain the Department of Conservation’s support to protect the ecological area.

Mr Munro said being able to meet the stakeholders in June was moving "slightly in the right direction".

"We will then hopefully get some agreement with us all that something needs to be done."

"To us the science is perfectly clear that the Long Mac groyne worked and would work again," Mr Munro said.

ORC’s manager executive advice Andrea Howard said the regional council did not have a position on the effectiveness or otherwise of the Long Mac groyne system but it had recently met representatives of the Aramoana League to listen to their concerns and was due to meet representatives of the League, the Department of Conservation and Port Otago in June to discuss the matter further.