Timeline of the Great Piako Swamp

20,000 years ago - The Hauraki depression
The sea (the Firth of Thames) covered the northern part of the depression on the western side of the peninsula, while the Waikato River flowed through the southern part (the Hauraki Plains) to the Firth of Thames. Vast quantities of river-transported muds, sands and gravels were deposited on the Hauraki Plains. About 20,000 years ago, debris from a volcanic eruption at Rotorua blocked the Waikato River and redirected it to its present course through Hamilton to the Tasman Sea. The Waihou and Piako rivers are responsible for the recent alluvial deposits on the Hauraki Plains.

Kahikatea swamp
Great kahikatea forests occupied the higher ground of the swamps of the Hauraki Plains before the arrival of Europeans. Flax, raupō, sedges and mosses occupied areas where water was permanent rather than seasonal. The Kōpūatai Peat Dome, west and south-west of Paeroa, is the only lowland ecosystem in New Zealand that remains substantially intact.

Around 1250–1300 CE
The islands of the Hauraki Gulf and the Coromandel Peninsula were likely places of first landfall for Polynesian migrants around 1250–1300 CE.
The Waihou River was a ready-made highway and the vast swamp around it was a rich source of food. Despite the discomfort of living surrounded by water, the remains of many settlements are found along the river. Māori used sand and shells to raise settlements above high-water mark. The ‘swamp pā’ of Ōruarangi and Pāterangi at Kōpū, and Kākaramea at Hikutaiā, were then the largest pā.

November 1769 - James Cook
In November 1769, Lieutenant James Cook spent three weeks in the region. He observed the transit of Mercury at Whitianga, sailed around the Coromandel Peninsula into the Firth of Thames, and spent two days on the Waihou River. Botanist Joseph Banks declared the Hauraki Plains to be ‘the properest place we have yet seen for establishing a colony’.¹ The immense trees, good anchorages and fertile soils greatly impressed the visitors, whose glowing reports brought Hauraki to the attention of Europe.

1794 to 1837 - Timber Ships
Among the six timber ships known to have visited the Waihou River at this time were the Fancy in 1794, the Hunter in 1798 and the Royal Admiral in 1801. 1820, a vessel – HMS Coromandel – visited Hauraki for the more suitable kauri spars. It was followed by HMS Buffaloin 1833 and 1837. Sydney companies entered the Hauraki timber trade in the mid-1830s.

1815 - Missionaries
In 1815 the Rev Samuel Marsden made his first missionary reconnaissance up the Waihou River, followed by two more in 1820.

1830s - Traders
In the early 1830s, the first resident European traders arrived in the Firth of Thames: flax traders at the mouths of the Piako and Waihou rivers.

1869 - Sawmilling
In 1869, the Hauraki Sawmilling Company established a mill at Tūrua on the Waihou River. It was at the forest’s edge and had a deep anchorage for ocean-going ships. Bagnall Bros bought the mill in 1877 and developed it into one of the largest in the country’s history.

1899 - Change of Name 
In 1899, Mr H. D. M. Hazard, FRGS ran some trial levels on the Hauraki Plains and induced the Chief Surveyor to come and inspect the area, and from then on he kept urging the Lands Department to undertake a drainage scheme. He claimed to have suggested the name "Hauraki Plains" to avoid confusion with the "Piako Swamp" between Hamilton and Morrinsville.

1908-1910 - Land Acts
The Hauraki Plains Act 1908 and the Waihou and Ohinemuri Rivers Improvement Act 1910 provided the necessary legal machinery for the Crown’s Hauraki Plains drainage scheme.

1910s - Land alienation
The Crown purchased most of the remaining Māori land in the Hauraki Plains in the 1910s.

1910 - 1914 - Land distribution
In one of the largest and most successful land development schemes in the country, more than 15,000 hectares was distributed to 270 settlers between 1910 and 1914.
My great-grandfathers were both successful in the 1910 land ballot, with lots beside each other at the bottom of the Firth of Thames.

1928 - Kōpū bridge
The Kōpū bridge across the Waihou River, which filled the final gap in the Auckland–Thames road in 1928, sealed the transition from river (and rail) to road transport in the region.

^{1. Joseph Banks, ‘Bank’s description of places.’ http://southseas.nla.gov.au/journals/banks_remarks/195.html (last accessed 8 November 2010).}

^{Paul Monin, Hauraki–Coromandel region, Te Ara – the Encyclopedia of New Zealand, https://teara.govt.nz/en/hauraki-coromandel-region (accessed 17 July 2025).
Story by Paul Monin, published 13 December 2010, updated 1 April 2016.}