Manukau Harbour is the second largest natural harbour in New Zealand and the sixth largest in the world by area. It is located to the southwest of the Auckland isthmus, and is an arm of the Tasman Sea.
The harbour mouth is between the northern head ("Burnett Head" / "Ohaka Head") located at the southern end of the Waitakere Ranges and South Head at the end of the long Awhitu Peninsula reaching up from close to the mouth of the Waikato River. The mouth is only 1800 metres wide, but after a nine kilometre channel it opens up into a roughly square basin 20 kilometres in width. The harbour has a water surface area of 394 square kilometres. There is a tidal variation in depth of up to 4 metres, a very substantial change, especially since the harbour, being silted up with almost 10 million years of sedimentation, is rather shallow itself.
Because of the large harbour area and narrow mouth between the Manukau Heads, tidal flow is rapid and a bar at the mouth makes navigating in or out of the harbour dangerous. New Zealand's most tragic shipwreck occurred on the bar in 1863 when HMS Orpheus ran aground in clear weather with a loss of 189 lives. For this reason, along with the harbour's shallowness, it is not Auckland's favoured port, and the facilities at Onehunga are not very large compared to the other Ports of Auckland facilities on the Waitemata Harbour on the northeast of the isthmus.
The harbour has three main arms - the Mangere inlet at the northeast lies close to Auckland's central city area, and the inner suburbs of Onehunga and Te Papapa are situated close to its northern shore. To the south of this arm lies the Otahuhu and Mangere urban areas. This arm is crossed by the Mangere Bridge. In the southeast is the Papakura Channel, which extends into the urban area of Papakura. In the southwest a further inlet known as the Waiuku River reaches south to the town of Waiuku. Auckland International Airport is located close to the harbour's eastern shore.
The harbour was an important historical waterway for the Māori. It had several portages to the Pacific Ocean and to the Waikato River, and various villages and Pās clustered around it. Snapper, flounders, mullet, and shellfish like as scallops, cockles, and pipis, provided food in plentiful amounts.
European settlement of the area was almost totally an outgrowth of the Waitemata Harbour-centred settlement, as these settlers spread south and west through the Isthmus and reached the Manukau Harbour. One of the few early settlements was Onehunga, from were some raiding of enemy settlements occurred during the Māori Wars, and which later became a landing point for Kauri and other products landed here by ship and canoe from the south. However, the combination of the difficult entry into the harbour, as well as the extension of the railway to Onehunga in 1873 made naval traffic on the harbour less important again, though the Port of Onehunga can trace its origins to this time.
Taking the idea of the several Māori portage paths over the isthmus one step further, a potential Manakau Harbour-Waitemata Harbour canal was considered in the the early 1900s, and legislation, the Auckland and Manukau Canal Act 1908, was passed that would allow authorities to take privately owned land where it was deemed required for a canal. However, no serious work (or land take) was undertaken. The act is technically still in force as of 2008.
The harbour is popular for fishing, though entry to the water is difficult with few all-tide boat ramps; often local beaches are used. Cornwallis, beside the Puponga Peninsula, was the first site for the future city of Auckland. However because of fraudulent land sales and rugged conditions, the settlement was abandoned in the 1840s. The surrounding bush clad hills had vast amounts of kauri removed for milling and was shipped from a wharf on Paratutai to either the other end of the Manukau Harbour at Onehunga for use in house building in the new city of Auckland, or along the coast to other New Zealand settlements. The last mills were abandoned in the early 1920s.
A new road-rail crossing of Manukau harbour is being considered in preparation for the 2011 rugby world cup.(New Zealand)
Mar 01, 2007; A new road-rail crossing of Manukau harbour is being considered in preparation for the 2011 rugby world cup. However, the current...