View of Whangarei Harbour from Mount Manaia, looking west over Mcleod Bay
|• Total||101.48 km2 (39.18 sq mi)|
Many early settlers and Maori used the harbour as a form of transport, and this played a large role in the establishment of Whangarei, and many of the industries in the area. These include Portland Cement Works, Marsden Point Oil Refinery and for the extraction of coal from Kamo.
From 1911-1933 the Onerahi Branch Railway crossed the upper reaches of the harbour to provide rail access to a new wharf built at Onerahi, as the existing wharf in the town basin was unreachable for some craft. This further promoted the harbour as an important feature to the development of Whangarei.
In 2006, two marine reserves were opened in Whangarei Harbour. Whangarei Harbour Marine Reserve is located in an inter-tidal area between Onerahi and Waikaraka, and another around Motukaroro Island, at Reotahi, Whangarei Heads. The Motukaroro Island reserve is popular with snorkelers due to the large amount of marine life seen there.
Whangarei Harbour stretches approximately 23 km north-west from Whangarei Heads to its farthest point inland at the town basin in Whangarei central. At its widest point it is approximately 6 km wide, between Parua Bay and Takahiwai, near One Tree Point.
The harbour is heavily tidal with a tidal range of approximately 2m, with much of the harbour being shallower than this in the wider parts. This means during low tide much of the harbour is mud flats and exposed sand bars. However, at the harbour entrance, where it is only around 800m wide, and between Onerahi and Matakohe Island, where it is only around 500m wide, it is up to 20m deep and currents can be strong.
The main rivers flowing into the harbour are Hātea River, Mangapai River, Limeburners Creek, Raumanga Stream and Otaika Creek. They carry lots of sediment from surrounding farmland, creating the muddy nature of the harbour, and this requires dredging in some parts for navigation purposes.