A half-graben is a geological structure bounded by a fault along one side of its boundaries, unlike a full graben where a depressed block of land is bordered by parallel faults.
59-662: The Hauraki Plains are a geographical area located in the northern North Island of New Zealand , at the lower (northern) end of the Thames Valley . They are located 75 kilometres south-east of Auckland , at the foot of the Coromandel Peninsula and occupy the southern portion of a rift valley bounded on the north-west by the Hunua Ranges , to the east by the Coromandel and Kaimai ranges and to
118-580: A depth of over 1200 ft. You can still see evidence of sea beaches between Shelly Beach and Maukoro. Before the arrival of the European settlers, the Hauraki Plains was 400 km of peat and swamp land which acted as a big ponding area, through which ran two main rivers – the Waihou and Piako . Māori used the rivers for hundreds of years to get to the rich food resources in the swamp. When
177-450: A major lifeline for the plains in the early days and they are still a part of everyday life, though not nearly as much as they used to be. Dairy farming is the most important industry on the Hauraki Plains, providing the most income for the region. The sizes of dairy farms range from around 100 cows to over 500. 66% of the total land area of the plains is used in dairy farming. This equates to 779.34 km of land. Although dairy farming
236-623: A metre to more than twenty metres. It was a morass, the home of wild ducks and eels. Nevertheless, the rich flora and fauna of the plains amply provided the staples of the Māori people who lived in the region. Many areas on the banks of the Waihou River were settled by Hauraki Māori , such as Oruarangi pā and Paterangi pā near Matatoki , and the Te Raupa pā and Waiwhau pā near Paeroa . The early European colonists were attracted not necessarily by
295-474: A population density of 8.8 people per km. Before the 2023 census, these statistical areas had a smaller boundary, covering 520.80 km (201.08 sq mi). Using that boundary, these three statistical areas had a population of 4,053 at the 2018 New Zealand census , an increase of 243 people (6.4%) since the 2013 census , and an increase of 90 people (2.3%) since the 2006 census . There were 1,479 households, comprising 2,067 males and 1,986 females, giving
354-473: A sex ratio of 1.04 males per female, with 927 people (22.9%) aged under 15 years, 720 (17.8%) aged 15 to 29, 1,848 (45.6%) aged 30 to 64, and 561 (13.8%) aged 65 or older. Ethnicities were 86.6% European/ Pākehā , 20.2% Māori , 2.5% Pacific peoples , 3.4% Asian , and 1.9% other ethnicities. People may identify with more than one ethnicity. The percentage of people born overseas was 10.8, compared with 27.1% nationally. Although some people chose not to answer
413-709: A whole. During the Last Glacial Period when sea levels were over 100 metres lower than present day levels, the North and South islands were connected by a vast coastal plain which formed at the South Taranaki Bight . During this period, most of the North Island was covered in thorn scrubland and forest , while the modern-day Northland Peninsula was a subtropical rainforest . Sea levels began to rise 7,000 years ago, eventually separating
472-581: A wire rope stretched across the river which originally had a Māori canoe tied to it on which people could pull themselves across and was later replaced by a punt with a crank and for two shillings people could crank themselves across. Geologists have shown that a very long time ago, the Waikato river came through the Hinurea valley and filled the Hauraki Basin with pumice, mud, drift wood and gravel to
531-465: Is in the North Island", "my mother lives in the North Island". Maps, headings, tables, and adjectival expressions use North Island without "the". According to Māori mythology , the North and South Islands of New Zealand arose through the actions of the demigod Māui . Māui and his brothers were fishing from their canoe (the South Island) when he caught a great fish and pulled it right up from
590-474: Is one of the two main islands of New Zealand , separated from the larger but less populous South Island by Cook Strait . With an area of 113,729 km (43,911 sq mi), it is the world's 14th-largest island , constituting 43% of New Zealand's land area. It has a population of 4,077,800 (June 2024), which is 76% of New Zealand's residents, making it the most populous island in Polynesia and
649-675: Is protected by the Wetland Management Reserve under the Conservation Act 1987 and is managed by the Department of Conservation. Fifty four species of birds have been recorded in the Kopuatai Peat Dome. Twenty seven are protected, 17 are unprotected and 10 are game birds. The endangered Australasian bittern ( Botaurus poiciloptilus ) is found in the wetland with other endangered birds such as
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#1732772136579708-632: Is the main industry it is not the only farming industry. Sheep and dry stock farming are beginning to catch on with farmers. There is still the demand for wool and meat, which the Hauraki Plains region helps to provide. An ostrich farm has been developed near Turua which deals in tourism, meat sales and gifts. There are primary schools in Ngatea , Kaihere , Pipiroa , Waitakaruru and Turua . Secondary education options include Hauraki Plains College in Ngatea, Paeroa College , and Thames High School . In
767-448: The 28th-most-populous island in the world. Twelve main urban areas (half of them officially cities) are in the North Island. From north to south, they are Whangārei , Auckland , Hamilton , Tauranga , Rotorua , Gisborne , New Plymouth , Napier , Hastings , Whanganui , Palmerston North , and New Zealand's capital city Wellington , which is located at the south-west tip of the island. The island has been known internationally as
826-608: The Hauraki Rail Trail , part of the New Zealand Cycle Trail , has been constructed in the Hauraki Plains. The largest town fully within the Plains is Ngatea , with a smaller settlement of Turua . The larger town of Paeroa is located on the eastern edge of the Hauraki Plains. While there is no defined geographical southern boundary to the Hauraki Plains, this is generally taken as being a line between
885-566: The North Island for many years. The Te Reo Māori name for it, Te Ika-a-Māui , also has official recognition but it remains seldom used by most residents. On some 19th-century maps, the North Island is named New Ulster (named after Ulster province in northern Ireland) which was also a province of New Zealand that included the North Island. In 2009 the New Zealand Geographic Board found that, along with
944-466: The North Sea often contain a series of half-graben sub-basins, with the polarity of the dominant fault system changing along the axis of the rift. Often the extensional fault systems are segmented in these rifts. Rift border faults with lengths over 10 kilometres (6.2 mi) are separated by relay ramp structures. The relay ramps may provide pathways for sediment to be carried into the basin. Typically
1003-539: The Piako and Waihou rivers, which flow north to reach the sea at the Firth of Thames , and earlier by the ancestral Waikato River. The resulting land is flat, peat-heavy, and partly swampy, which has been converted into excellent land for dairy farming. Economically, the dairy farming is the leading primary industry, supported by other grassland farming. More recently, tourism in the Hauraki Plains region has been growing and
1062-679: The Waikato region, mostly within the Waikato , Matamata-Piako and Hauraki Districts. Five of New Zealand's wetlands are listed on the International Convention on Wetlands of International Importance (Ramsar sites); there are three of them in the Waikato Region: At 9,238.44 hectares, the Kopuatai Peat Dome is New Zealand's largest unaltered restiad peat bog, and is also globally unique. The area
1121-474: The banded rail ( Rallus philipensis assimillis ), marsh crake ( Porzana pusilla affinis ) and the North Island fernbird ( Bowdleria punctata vealeae ). 37°17′S 175°30′E / 37.283°S 175.500°E / -37.283; 175.500 North Island The North Island ( Māori : Te Ika-a-Māui [tɛ i.kɐ ɐ mɑː.ʉ.i] , lit. 'the fish of Māui', officially North Island or Te Ika-a-Māui or historically New Ulster )
1180-640: The "lofty trees which adorn its banks". He was the first European to travel up the river. The Waihou reminded him of the River Thames in London so he named it the River Thames. Although this name stuck for quite some time, now it is known as the Waihou. His discovery of the kahikatea tree later brought many ships to the area looking for masts and spars. In the 1900s the Waihou was navigable right up to Matamata , because development had not yet silted up
1239-481: The 1840s an estimated 1100 km of wetland covered the lower Waikato area and Hauraki Plains. Since then 85 to 90% of New Zealand wetlands have been lost. The Department of Conservation (DOC) estimates of wetlands that remain in the Waikato are around 320 km, approximately 25% of their original area. This figure includes Whangamarino (5,130.35 hectares), and Kopuatai Peat Dome (9,238.44 hectares). Roughly 80% of New Zealand's remaining wetlands are in areas across
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#17327721365791298-590: The 2023 census, 63.1% of North Islanders identified as European ( Pākehā ), 19.8% as Māori , 10.6% as Pacific peoples , 19.3% as Asian , 1.9% as Middle Eastern/Latin American/African, and 1.1% as other ethnicities. Percentages add to more than 100% as people can identify with more than one ethnicity. Māori form the majority in three districts of the North Island: Kawerau (63.2%), Ōpōtiki (66.2%) and Wairoa (68.5%). Europeans formed
1357-461: The Europeans came they also used the rivers for transport. Because the Hauraki Plains were swamp land and there were no roads the easiest way to transport people, supplies, food and produce was by boat. Gold brought many ships up the Waihou and Ohinimuri rivers with heavy machinery and miners aboard. There was even a special hard wharf built at Paeroa for fear of a conventional one collapsing while
1416-479: The Government to drain the land, but the Government said it could never be done, as parts of the Hauraki Plains were two metres below sea level. However, in 1908 an act was passed to give the people permission to drain the land. The Government paid the workers to dig the drains, a process that took ten years to complete. In 1910, the Government decided to open an area of 16,299 acres (66 km) for settlement on
1475-546: The Hauraki Basin slowly filled up with pumice, mud and gravel. After the last shift of the Waikato River back to the west coast, the Waihou and Piako rivers were formed. These two rivers carried silt out into the Firth of Thames or Tikapa. The plains were full of mangroves , raupo ( Typha orientalis ), harakeke ( Phormium tenax ) a dense forest of kahikatea . Most of the land was raw peat, varying in depth from
1534-578: The Hauraki Plains. Ballots were held for the blocks, which attracted the interests of future settlers and businessmen in the Thames Valley . Miners in the South Island were keen to settle in the area if sections were drawn up by the Government. The first applications for land blocks were made at the Miner's Union Hall in Thames on 18 May 1910. Prices ranged from $ 10–$ 15 an acre, depending on how much land
1593-594: The North Island is provided by fifteen District Health Boards (DHBs) . Organised around geographical areas of varying population sizes, they are not coterminous with the Local Government Regions . Half-graben A rift is a region where the lithosphere extends as two parts of the Earth's crust pull apart. Often a rift will form in an area of the crust that is already weakened by earlier geological activity. Extensional faults form parallel to
1652-519: The South Island, the North Island had no official name. After a public consultation, the board officially named it North Island, or the aforementioned Te Ika-a-Māui, in October 2013. In prose, the two main islands of New Zealand are called the North Island and the South Island , with the definite article. It is also normal to use the preposition in rather than on , for example "Hamilton
1711-437: The South Island, this is solely due to the North Island having higher natural increase (i.e. births minus deaths) and international migration; since the late 1980s, the internal migration flow has been from the North Island to the South Island. In the year to June 2020, the North Island gained 21,950 people from natural increase and 62,710 people from international migration, while losing 3,570 people from internal migration. At
1770-462: The South Island, with the country's largest city, Auckland, and the capital, Wellington, accounting for nearly half of it. There are 30 urban areas in the North Island with a population of 10,000 or more: The sub-national GDP of the North Island was estimated at NZ$ 282.355 billion in 2021 (78% of New Zealand's national GDP). Nine local government regions cover the North Island and its adjacent islands and territorial waters. Healthcare in
1829-403: The axis of the rift. An extensional fault may be seen as a crack in the crust that extends down at an angle to the vertical. As the two sides pull apart, the hanging wall ("hanging over" the sloping fault) will move downward relative to the footwall. A rift basin is created as the crust thins and sinks. In the rift basin, warm mantle material wells up, melting the crust and frequently triggering
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1888-425: The basin wall. Other material is transported across or along the basin to the deep water parts of a rift lake along the escarpment margin. Most of the sediment will enter the half-graben along the unfaulted hanging wall side. On the side of the basin opposite the main border fault, sedimentation occurs along the "hinged margin", which may also be called the "shoaling margin" or the "flexural margin". In this part of
1947-449: The basin, slopes are usually gentle and large river systems may carry sediment into the basin, which could be stored in deltas where they enter a rift valley lake. Littoral and sub-littoral carbonate deposits may accumulate in these conditions. The "axial margins" at the ends of basins often include low-gradient ramps where major rivers enter the basin, building deltas and form currents within a rift lake that can carry sediment from one end to
2006-456: The census's question about religious affiliation, 59.5% had no religion, 26.6% were Christian , 1.9% had Māori religious beliefs , 0.2% were Hindu , 0.3% were Buddhist and 2.2% had other religions. Of those at least 15 years old, 315 (10.1%) people had a bachelor's or higher degree, and 807 (25.8%) people had no formal qualifications. 417 people (13.3%) earned over $ 70,000 compared to 17.2% nationally. The employment status of those at least 15
2065-411: The circumnavigation of New Zealand. The maps described the North Island as " Ea Heinom Auwe " and " Aeheinomowe ", which recognises the "Fish of Māui" element. Another Māori name that was given to the North Island, but is now used less commonly, is Aotearoa . Use of Aotearoa to describe the North Island fell out of favour in the early 20th century, and it is now a collective Māori name for New Zealand as
2124-451: The conclusion of the Otago gold rush in the 1860s, New Zealand's European population growth has experienced a steady 'Northern drift' as population centres in the North Island have grown faster than those of New Zealand's South Island. This population trend has continued into the twenty-first century, but at a much slower rate. While the North Island's population continues to grow faster than
2183-412: The eruption of volcanoes. Extensional basins may appear to be caused by a graben, or depressed block of land, sinking between parallel normal faults that dip towards the center of the graben from both sides. In fact, they are usually made of linked asymmetrical half-grabens. Faults with antithetic slope directions linked in to a controlling fault, or periodic changes of dip in the controlling faults, give
2242-503: The impression of full graben symmetry. As the rift expands, the rift flanks lift up due to isostatic compensation of the lithosphere . This creates the asymmetric topographic profile that is typical of half grabens. The half grabens may have alternating polarities along the rift axis, dividing the rift valley into segments. Intracontinental and marine rift basins such as the Gulf of Suez , East African Rift , Rio Grande rift system and
2301-660: The islands and linking the Cook Strait to the Tasman Sea . The North Island has an estimated population of 4,077,800 as of June 2024. The North Island had a population of 3,808,005 at the 2023 New Zealand census , an increase of 213,453 people (5.9%) since the 2018 census , and an increase of 570,957 people (17.6%) since the 2013 census . Of the total population, 733,893 people (19.3%) were aged under 15 years, 743,154 (19.5%) were 15 to 29, 1,721,427 (45.2%) were 30 to 64, and 609,534 (16.0%) were 65 or older. Ever since
2360-500: The land, but by the dense forest of kahikatea. The colonists, or Pakeha, were timber millers such as the George and Martha Bagnall family who settled at Turua in 1875. As the kahikatea was felled, farmers followed onto the newly cleared land. But, once a year, the Waihou and Piako Rivers would overflow, making agricultural settlement of the area difficult because of the poor drainage. The people who lived around Hauraki wanted permission from
2419-463: The last town accessible by boat was Patetonga. Supplies were brought up the Piako by a small yacht and later by a launch. The boat was the main outlet to civilisation for the settlers who were mostly male bachelors and it was easier for them to eat stale bread brought up by the boat weekly than to make it themselves. It also brought mail and took cream back to Kopu which took four hours. The rivers were
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2478-412: The machines were unloaded. Bagnells' mill at Turua was established to mill the tall kahikatea trees growing there. Huge barques (sailing ships) came up the river on flood tides to collect the wood, some of which would be taken to Australia and be made into butter boxes. After the scrub and kahikatea had been cleared farming was taken up and the farmers needed everything from food to animals and boats and
2537-458: The main drains, which brought the water out and into the canals. Floodgates were installed to prevent the ingress of water into the canals, while allowing floodwaters to flow out of the system. As a result of the drainage system, the size of the wetlands declined to less than 25% of their original area. Once the land was mostly drained, scrub, logs and tree stumps had to be cleared, and the earth levelled, to convert it to pasture. The scrub and waste
2596-516: The major bounding fault, since uplift of the footwall causes the land on the footwall side to slope away from the fault. Rivers on that side therefore carry sediment away from the rift valley. But as the lowest part of the basin with the greatest rate of subsidence, the escarpment margin experiences the highest rates of sedimentation, which may accumulate to several kilometers in depth. This sedimentation often includes very coarse debris such as huge blocks from rock falls, as well as fans of sediment from
2655-544: The mining in Waihi) bigger ships were required to carry the bigger loads. The majority of the boats were steamers, but some were paddle steamers. Larger passenger ships had luxurious lounges for men and women decorated with velvet upholstery and paintings on the walls. There were even brass bands on some boats and room for dancing on the decks. There was also room for horses and general cargo. Some cargo boats and punts were designed with drop sides to assist in loading and unloading on
2714-403: The other. Between adjacent half grabens there will be "accommodation zones" that may include local extension, compression or strike-slip faulting. These can create complex morphologies within which different mechanisms affect sedimentation. The types of sedimentation in half grabens also depend on lake levels in the rift, the climate (e.g. tropical versus temperate) in which the sediments form and
2773-470: The plurality in the Auckland region (49.8%) and are the majority in the remaining 39 districts. The proportion of North Islanders born overseas at the 2018 census were 29.3%. The most common foreign countries of birth were England (15.4% of overseas-born residents), Mainland China (11.3%), India (10.1%), South Africa (5.9%), Australia (5.5%) and Samoa (5.3%). The North Island has a larger population than
2832-560: The remains of the wharf where the ships berthed. When the Bagnalls first arrived in Turua and wanted to go to church in Thames, they rowed to Kopu then walked the last five miles (8.0 km) to Thames. At Orchard (now called Ngatea ), Pipiroa, Kopu and Paeroa there were punts (floating platforms) that carried people, horses and carts across the rivers for a small fee. At Te Aroha, there was
2891-414: The rift is broken along its axis into segments about 50 to 150 kilometres (31 to 93 mi) long. Four zones of sedimentation can be defined in a half-graben. The first is "escarpment margin" sedimentation, found along the major border faults bounding the half graben, where the deepest part of the basin meets the highest rift-shoulder mountains. Comparatively little sediment enters the half-graben across
2950-453: The river banks. This was especially useful when animals were being loaded. During the mining strike the hotels were closed by the government, but you could still drink on a moving boat. So people would get on the boats and take a trip for the day just to use the bar. In 1877, massive timber ships called barques travelled up to Bagnalls' mill in Turua to collect the kahikatea logs and transport them to Auckland and Australia. You can still see
3009-429: The river. Travelling up stream you would pass Kopu on the left then Turua on the right, Matatoki , Puriri , Hikutaia , Paeroa and Te Aroha on the left and eventually Matamata on the right. The Piako River is much smaller than the Waihou, but it was just as important in the development of the Hauraki Plains. Travelling up the Piako you would see Pipiroa, then Ngatea, both on the right, followed by Kerepehi, and
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#17327721365793068-470: The rivers carried it all in. In pioneer days the rivers were the lifelines of the Hauraki Plains, but as roads improved and bridges were built the need for river transport diminished. Today it has all died away except the ferry that goes up the Waihou to Paeroa from Auckland, and the metal barge that comes into Kopu to pick up a load. In 1769 Captain James Cook travelled up the Waihou River to look at
3127-427: The sea. While he was not looking, his brothers fought over the fish and chopped it up. This great fish became the North Island, and thus a Māori name for the North Island is Te Ika-a-Māui ("The Fish of Māui"). The mountains and valleys are believed to have been formed as a result of Māui's brothers' hacking at the fish. During Captain James Cook 's voyage between 1769 and 1770 , Tahitian navigator Tupaia accompanied
3186-458: The towns of Te Aroha and Morrinsville , approximately following State Highway 26. Three statistical areas cover the northern part of Hauraki Plains: Hauraki Plains North , Hauraki Plains East and Hauraki Plains South . They include Turua , Kaihere , Kerepehi , Pipiroa and Waitakaruru , and surround but do not include Ngatea . They cover 522.47 km (201.73 sq mi) and had an estimated population of 4,610 as of June 2024, with
3245-420: The water chemistry. Although sediments arrive primarily from the unfaulted side of the half-graben, some erosion takes place on the fault escarpment of the main border fault, and this produces characteristic alluvial fans where confined channels emerge from the escarpment. Lake Baikal is an unusually large and deep example of half-graben evolution. The lake is 630 by 80 kilometres (391 by 50 mi), with
3304-708: The west by a series of undulating hills which separate the plains from the much larger plains of the Waikato River . The Plains are not presently a single administrative area, though a Hauraki Plains County Council existed from 1920 to 1989 and a statistical Area Unit remains. Broadly, the northern and southern parts of the Hauraki Plains are administered by the Hauraki District and the Matamata-Piako District respectively. The alluvial plains have been built up by sediment deposited by
3363-623: Was being bought and the location of the block. Some of the most sought-after blocks had up to 99 applicants. Work started immediately after the passing of the Hauraki Plains Act. Controlling the flooding of the Piako River which overflowed at least once a year was crucial. This was achieved through the construction of stop-banks to prevent floods and tidal overflow. Farmers were required to dig drains, ranging from one to two metres wide, through their land. These drains connected to
3422-413: Was burnt off. River transport was the most effective method to transport goods, people and animals to the Hauraki Plains, as an effective roading system had not yet been established. Ships of all sizes plied the rivers of the Hauraki Plains, from tiny row boats to huge barques although, most of the boats were steamers and the engines were made at A & G Price in Thames. As industries progressed (like
3481-609: Was that 1,638 (52.4%) people were employed full-time, 510 (16.3%) were part-time, and 87 (2.8%) were unemployed. Around 2–3 million years ago, a large block of the crust slumped down 500–2000 metres, forming in due course the Hauraki 2 to 3 half-grabens . The ancestral Waikato River often flowed through the resulting valley into the Hauraki Gulf, most recently through the Hinuera Valley some 20,000 years ago. Over time,
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