Council halts work on coastal shaping

00:15, Nov 23 2012

Spiralling cost has seen Tasman call a halt to further coastal modelling in its investigation of a long-term solution to the erosion of Jackett Island.

Councillors at the district's engineering services meeting yesterday also heard it was possible no long-term work to stop the erosion may be carried out if the final solutions were deemed financially unsustainable.

A report by transportation manager Gary Clark to the meeting said $132,294 had already been spent on legal, staff and consultancy fees to investigate, validate, calibrate and discuss solution options including a proposal to create a channel through the existing sandbar. Around $30,000 of the cost covered maintaining a temporary sandbag wall in front of the Van Dyke family's threatened island home.

The matter has been driven by a successful Environment Court case taken by the Van Dyke family which argued their island home was being threatened by erosion caused by a council groyne built on the northern side of the Port Motueka channel in the late 1990s.

A sandbar has since curved south offshore of the island channelling water from the Moutere estuary across the island's foreshore and reducing all-tide access to Port Motueka.

Mr Clark told the meeting that a six-member expert panel, largely representing the views of stakeholders, had agreed a channel cut through the spit directly opposite the port was a plausible solution.


Modelling showed the channel would reduce the velocity of water along the island's foreshore but was unlikely to see the island's beach replenished. Sand would have to be mechanically shifted to recreate the island's beach, he said.

The experts, except for the Van Dyke family's Dr Bob Kirk, agreed there was little need to also model a channel cut further to the north, he said.

Councillors agreed and passed the resolution not to model a possible channel to the north of the port.

Mr Clark said the experts generally felt that coastal environment was complex, dynamic and there had been a history of erosion on the island.

The full report on the possible long-term solutions and costs would be presented to the council in February, he said.

The report would include the analysis and cost of options such as property purchase and the relocation of homes and cutting a channel through the spit.

But it was possible staff could recommend that none of the options was viable if the final cost was too high, he said.

Meanwhile a second staff report to the meeting showed removing Port Motueka's geotextile groyne, which was ordered by the court, had cost ratepayers more than $600,000.

Councillors agreed to leave the report on the groyne's cost until February's engineering meeting as accounts for its removal were still being received by the council.

However, the report revealed that the council's corporate services committee had, in committee earlier this month, approved spending $393,000 from the Motueka Harbour and Coastal Works Account (the former Port Motueka Endowment Fund) to help pay for the groyne's removal.

Motueka Community Board chairman David Ogilvie questioned why the money had come from Motueka's coast works account. He considered the issue was a district-wide project.

Chairman Trevor Norriss said the situation had been discussed.

Mr Ogilvie said it had been discussed in committee and only now come to light.

The Nelson Mail