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It’s that time of year again. Sand build-up at Bullet Point, near the northern inlet of Mangawhai Harbour, is being dredged and used to strengthen the bund wall on the distal spit (Mangawhai’s iconic sand dunes). This is good news for boaties, beachgoers, the health of the estuary, sand dunes, marine and bird life. A big part of the magic of Mangawhai is our beautiful harbour and sand dunes.
Restoring and maintaining them has been the focus of our small volunteer organisation since Cyclone Bola in 1988 breached the spit and closed the northern inlet, prompting the infamous 1991 ‘big dig’. Over the next 30 plus years, ongoing efforts by MHRS has prevented the northern inlet choking and the sand spit breaching again.
Annually, we use our dredger Spirit of Mangawhai II to clear sand in resource-consented areas of the harbour inlet and estuary. This has many benefits for this wonderful ecosystem, including improved water flow and quality, sustaining marine and bird life habitats, as well as enhancing boating, swimming, fishing and other recreational use of our stunning harbour.
This dredged sand is recycled to restore and maintain the distal spit, which continues to be eroded by channel movement and storms. Our recent in-depth aerial survey revealed that 420,000 tonnes of non-replenishing sand has been lost from the sand spit. The distal spit provides essential protection for the estuary from the sea, while planned placement of the sand on the spit creates bird nesting habitats. It’s a win win for all.
Over the past four years a considerable build-up of sand has arisen where the two channels in the estuary meet, locally known as Bullet Point. As it is dredged, the sand is piped to and placed on the eastern side of the distal spit bund wall.
The temporary sand delivery pipe has been sunk in the channel to enable boat navigation. Buoys identify the navigable part of the channel and at night, red and green beacon lights show the channel location. These activities are consented by the Department of Conservation and Northland Regional Council, and will continue until July 31.
In addition to this scheduled work, MHRS volunteers continue to stabilise the distal spit by planting native spinifex and pingao plants on both sides of the dunes. More net fencing installation is planned to further stabilise the sand dunes by collecting wind-blown sand drifts.
The planting and fencing programmes are supported by DOC and are designed to complement the sandspits bird sanctuary.
