At its prime Mangawhai Harbour provided a waterway used by the local community to transport goods from a thriving community to its market in Auckland. With the main trunk railway extending to nearby Kaiwaka in the 1920's, Mangawhai Harbour was no longer needed as a port and, with the deforestation of the 'sandspit' and the change of land use from forest to pastoral in the catchment area, the harbour began to change.
Sand began to make the harbour shallow and flood prone, erosion caused the sandspit to be breached, and the harbour entrance became blocked in the 1980's. Mangroves engulfed areas of tidal estuary, trapping mud and displacing shellfish. The estuarine ecosystem was in imbalance and the biodiversity was being lost.
Although the Mangawhai Harbour Society wasn't properly formed until 1990, the concept was already in place in 1978 when local residents, concerned at the deterioration of the harbour, teamed up to take action necessary to remedy the problem. After initial failure, with dogged perseverance and sound planning, the fledgling MHRS gained acceptance from local authorities and began to reach solutions that met all parties' objectives.
The first challenge was to re-open the blocked entrance to Mangawhai Harbour and seal up the breached south entrance. This, in line with an on-going management plan, has been followed by other initiatives in an effort to sustain the fragile ecology of Mangawhai Spit and Harbour.
