Posted on April 23, 2026
Mangawhai Harbour Restoration Society (MHRS) has started its annual dredging and sandspit stabilisation programme, continuing more than three decades of work to safeguard the harbour’s health.
The Spirit of Mangawhai II dredge was deployed mid-March, with operations scheduled through to July 31. Work is timed for autumn and winter to avoid disturbing the breeding season of the critically endangered fairy tern and other shorebirds.
New data from University of Auckland LiDAR surveys shows the sandspit has lost 420,000 tonnes of sand over six years, with six areas now at risk of breaching. MHRS is using dredged sand to reinforce two of these vulnerable zones, followed by dune stabilisation using sand fencing and native plantings.
The dredging also maintains tidal flow, helping prevent erosion and keeping the harbour navigable. Without intervention, experts warn the harbour could stagnate, threatening both wildlife and water quality.
Boaties are advised to follow updated navigation routes and signage near Alamar and Sellars Reserve to ensure safety around dredging operations.
MHRS says the project is vital not only for navigation, but for preserving a key coastal ecosystem and protecting endangered species.
