Sand dredging inside Whangamata Harbour is threatening the renowned Whangamata bar, say surfing advocates who are calling for urgent action.
Surfbreak Protection Society, a national body dedicated to preserving the country's surfbreaks, has called on the regional council to beef up its monitoring of dredging in the harbour.
Society president Paul Shanks said anecdotal evidence of a deterioration in "wave quality" at the Whangamata bar appeared linked to dredging by Whangamata Marina developers.
"Our concern is the maintenance dredging of the marina access channel has upset the natural sediment cycle and as a result the bar has become unstable," Mr Shanks told the Times.
"Over the past three years surfers have noticed the wave quality has deteriorated and what we're saying is more science is needed to find out why that is. More science means more monitoring and at the moment we don't think the regional council's current monitoring regime is adequate."
Whangamata's famous peeling wave action is created by a combination of a large tidal delta sand bar alongside a harbour channel entrance which interacts with sediment flow in and out of the tidal estuary.
The society has asked the Waikato Regional Council to attend a workshop to discuss their concerns.
Regional council's consented sites division manager Brent Sinclair said the council carried site inspections, as well as reviewed data supplied by the Whangamata Marina Society, to ensure the society complied with consents granted by the environment minister.
Mr Sinclair said the marina society's dredging-related activities had shown a "high level" of compliance with the consent conditions. The council took into account bar monitoring work when assessing compliance.
"The experts acknowledge that the ebb tide delta, commonly known as the bar, is a dynamic environment and can be affected by many naturally occurring events, such as storms and large waves," he said. "While we acknowledge the comments by the Surfbreak Protection Society in relation to changes in surf quality, our scientists have seen no clear scientific evidence that the Whangamata bar has been adversely affected by dredging."
In June the Surfbreak Protection Society produced a report on the Whangamata bar which concluded the feature had reached its "tipping point".
The report said: "The monitoring to date, although not thorough enough, has supported the anecdotal evidence of the surfers that the bar's amenity value has been seriously damaged. We now need to get a comprehensive monitoring plan to meet the needs of all stakeholders in this estuary."
Mr Sinclair said the report was being reviewed but did not appear to contain new scientific research.
- © Fairfax NZ News
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