Reef to go 'boom'

The number of boats hitting the reef in front of Waipapa Landing ramp, marked by the buoys in this photo, has increased sharply in recent months. Photo / Peter de Graaf

Explosives may be used to blow up a reef deemed a navigational hazard for boaties using a popular launch ramp at Kerikeri's Waipapa Landing.

Northland Regional councillor Dover Samuels, harbour master Jim Lyle and council staff inspected the reef earlier this month following a series of complaints from boaties saying they had damaged or lost their propellers.

The reef was marked but, because it was immediately in front of the boat ramp, it was not easy to avoid. At low tide, it almost breached the surface, Mr Samuels said.

The ramp could not be shifted and an underwater inspection, including by Mr Samuels in his snorkel gear, had shown the reef was solid basalt and not loose rocks that could be removed by machine.

Mr Samuels said he backed the plan to blow up the reef as long as he could be assured properties around the landing would not be affected and nearby residents would be notified.

"I don't want tuna [eels] landing on their lawns when they blow it up," he quipped.

Harbour master Jim Lyle said boaties had hit the reef for as long as he could remember, despite the buoys, but the number of incidents had increased in recent months. Mr Lyle believed it could have been an unforeseen consequence of a Far North Holdings project to improve the pontoon, which may have altered the line boaties took as they approached Waipapa Landing. Two extra buoys had been placed on the reef to little effect.

"It's got to the point where it really is a navigational hazard and we'd like to do something about it."

The most likely solution would be to drill holes into the basalt, insert explosives, then wait until high tide when the reef was under a few metres of water before detonating. That would ensure no debris went flying through the air. Once the basalt had been shattered, it could be dredged up from a barge.

Because removing the reef was outside the harbour master's normal operations, regional councillors would have to agree to fund it. A resource consent would also be required. Mr Lyle hoped the hazard would be gone in time for the 2016-2017 boating season.

The next closest boat ramps are at Rangitane, Dove's Bay and Opito Bay, all on the other side of Kerikeri Inlet.