The Estuary of the Heathcote and Avon Rivers / Ihutai is the largest semi-enclosed shallow

estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

Canterbury Canterbury (, ) is a City status in the United Kingdom, cathedral city and UNESCO World Heritage Site, situated in the heart of the City of Canterbury local government district of Kent, England. It lies on the River Stour, Kent, River Stour. ...

and remains one of New Zealand’s most important coastal wetlands. It is well known as an internationally important

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

for

migratory birds Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by ...

, and it is an important recreational playground and educational resource. It was once highly valued for ''mahinga kai'' (

Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the C ...

for food gathering).

Location

The

Avon River / Ōtākaro The Avon River / Ōtākaro ( and ) flows through the centre of the city of Christchurch, New Zealand, and out to an estuary, which it shares with the Ōpāwaho / Heathcote River, the Avon Heathcote Estuary / Ihutai. Course The Avon follows a me ...

enters the estuary from the northwest, and the

Ōpāwaho / Heathcote River The Ōpāwaho / Heathcote River lies within the city boundaries of Christchurch, New Zealand, and is fed from springs near Templeton Road, with a catchment area in wet weather extending as far west as Yaldhurst and Pound Road. It meanders around t ...

from the south-west. The estuary has a triangular shape, a short inlet connection with

Pegasus Bay Pegasus Bay, earlier known as Cook's Mistake, is a bay on the east coast of the South Island of New Zealand, to the north of Banks Peninsula. Toponymy Pegasus Bay takes its name from the brig ''Pegasus'', a sealing ship that was sailing fro ...

, and is primarily enclosed by the long Brighton Spit, on which the suburbs New Brighton,

South New Brighton South New Brighton is a coastal suburb on the eastern side of Christchurch city. The suburb was officially named in 1953, after a suggestion that it be called South Brighton was rejected because there is already Brighton near Dunedin. South Br ...

and Southshore are located. The most prominent features of the inlet are the single deep channel between Rapanui Rock ("Shag Rock") and Brighton Spit.

Description

It is shallow with the mean at high water of ordinary spring tides (HWOST) of —and is predominantly

intertidal The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of Marine habitat, habitats with var ...

, as only about 15 percent of the area lies below low water of ordinary spring tides (LWOST).

Official name

The estuary's official name became Estuary of the Heathcote and Avon Rivers / Ihutai as a result of the

Ngāi Tahu Claims Settlement Act 1998 The Ngāi Tahu Claims Settlement Act 1998 is an act of Parliament passed in New Zealand relating to Ngāi Tahu, the principal Māori (tribe) of the South Island. It was negotiated in part by Henare Rakiihia Tau. The documents in relation to the ...

History

The Land

The Estuary formed around 450 years ago and covers around 880 hectares (3.3 square miles). In 1989 the Canterbury Regional Council and the Christchurch City Council drilled an exploratory bore near the mouth of the Avon River / Ōtakaro discovering layers of fossils and sediment types that showed the area had experienced shifts between being marine, estuary, swamp and floodplain over the last 2 million years. The land underneath the Estuary consists of gravel embedded between fine silts and sands deposited by the rivers and sea. The Brighton Spit which encloses the Estuary was formed by sand carried by the Ashley / Rakahuri and Waimakariri Rivers and as the Spit grew, the mouth of the

was forced southward towards that of the Ōpāwaho / Heathcote River, forming the estuary of today.

Early Māori settlement

Māori people The Māori (, ) are the indigenous Polynesian people of mainland New Zealand (). Māori originated with settlers from East Polynesia, who arrived in New Zealand in several waves of canoe voyages between roughly 1320 and 1350. Over several ce ...

were the first settlers in

and arrived around the 13th century according to western archaeological evidence, though Māori

whakapapa Whakapapa (, ), or genealogy, is a fundamental principle in Māori culture. Reciting one's whakapapa proclaims one's Māori identity, places oneself in a wider context, and links oneself to land and tribal groupings and the mana of those. Exper ...

(genealogies) date settlement before this period of time with the discovery of the

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

by Waitaha ancestor,

Rākaihautū Rākaihautū was the captain of the canoe () and a Polynesian ancestor of various , most famously of Waitaha and other southern groups, though he is also known in the traditions of Taitokerau, and in those of Rarotonga. In Māori traditions ...

. Traditional food gathering or

mahinga kai Mahinga is a settlement in Kenya ) , national_anthem = " Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = ...

sites of Waitaha, Rapuwai, Kāti Mamoe and subsequently

Ngāi Tahu Ngāi Tahu, or Kāi Tahu, is the principal Māori (tribe) of the South Island. Its (tribal area) is the largest in New Zealand, and extends from the White Bluffs / Te Parinui o Whiti (southeast of Blenheim), Mount Mahanga and Kahurangi Poi ...

iwi included Ihutai (The Estuary). The nearest kāika (settlements) included Orua Paeroa at

Travis Wetland Travis Wetland is a wetland in the suburb of Burwood in Christchurch, New Zealand. An ecological restoration programme is being undertaken to restore the wetland. It covers 116 ha of land formerly drained and used as a dairy farm. In 2009 it won ...

and Te Kai a Te Karoro pā, which was located near to South New Brighton Park, the latter supporting iwi to reside there throughout each year due to the abundance of food supplied by Ihutai. Traditional food sources around Ihutai included pūtangitangi (

Paradise Shelduck The paradise shelduck (''Tadorna variegata''), also known as the paradise duck, or in Māori, is a species of shelduck, a group of goose-like ducks, which is endemic to New Zealand. Johann Friedrich Gmelin placed it in the genus ''Anas'' with ...

), pārera ( grey duck), tuna (

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

s), kanakana (

lamprey Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes , placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like s ...

), īnanga (adult

whitebait Whitebait is a collective term for the immature fry of fish, typically between long. Such young fish often travel together in schools along coasts, and move into estuaries and sometimes up rivers where they can be easily caught using fine-m ...

), patiki (

flounder Flounders are a group of flatfish species. They are demersal fish, found at the bottom of oceans around the world; some species will also enter estuaries. Taxonomy The name "flounder" is used for several only distantly related species, thou ...

) and pipi (shellfish). In former times a soft-shelled perwinkle snail called whetiko flourished. In March 1948 Governor

George Grey Sir George Grey, KCB (14 April 1812 – 19 September 1898) was a British soldier, explorer, colonial administrator and writer. He served in a succession of governing positions: Governor of South Australia, twice Governor of New Zealand, Go ...

negotiated sale of 20 million acres between

Kaiapoi Kaiapoi is a town in the Waimakariri District of the Canterbury region, in the South Island of New Zealand. The town is located approximately 17 kilometres north of central Christchurch, close to the mouth of the Waimakariri River. It is con ...

and

Otago Otago (, ; mi, Ōtākou ) is a region of New Zealand located in the southern half of the South Island administered by the Otago Regional Council. It has an area of approximately , making it the country's second largest local government reg ...

via the land purchaser Henry Kemp who obtained Māori signatures to a deed of purchase now referred to as Kemp's Purchase or

Kemp's Deed Kemp's Deed, also known as the Canterbury Purchase, Kemp's Purchase, or the Ngāi Tahu Purchase, is the purchase of Canterbury, New Zealand, from some Ngāi Tahu chiefs by Tacy Kemp on behalf of the New Zealand Company. It is the Crown's largest ...

. Governor Grey did not uphold all the terms of Kemp's Deed which included a promise to allow access to traditional mahinga kai and kaika nohoanga (seasonal camps) and by the 1850s Māori were barred from access to their mahinga kai sites around the estuary.

Early European settlement

Sealers and whalers were often valued by Māori who traded

flax Flax, also known as common flax or linseed, is a flowering plant, ''Linum usitatissimum'', in the family Linaceae. It is cultivated as a food and fiber crop in regions of the world with temperate climates. Textiles made from flax are known in ...

and

potatoes The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae. Wild potato species can be found from the southern United ...

for steel

adzes An adze (; alternative spelling: adz) is an ancient and versatile cutting tool similar to an axe but with the cutting edge perpendicular to the handle rather than parallel. Adzes have been used since the Stone Age. They are used for smoothing o ...

, axes,

muskets A musket is a muzzle-loaded long gun that appeared as a smoothbore weapon in the early 16th century, at first as a heavier variant of the arquebus, capable of penetrating plate armour. By the mid-16th century, this type of musket gradually dis ...

and other supplies and the Estuary provided an important trading route. In 1837, a whaler named James Robinson Clough also known as Jimmy Robinson married Puawai a local Māori and is said to be the first European to access the Estuary.

Avon–Heathcote Estuary Ihutai Trust

The Avon–Heathcote Estuary Ihutai Trust was formed in 2002. This resulted from requests from the wider community to act in the estuary’s long-term interests. The members of the Trust include representatives from the community, existing groups (Friends of the Estuary and the Christchurch Estuary Association), representatives from

Christchurch City Council The Christchurch City Council is the local government authority for Christchurch in New Zealand. It is a territorial authority elected to represent the people of Christchurch. Since October 2022, the Mayor of Christchurch is Phil Mauger, who ...

Environment Canterbury Environment Canterbury, frequently abbreviated to ECan. is the promotional name for the Canterbury Regional Council. It is the regional council for Canterbury, the largest region in the South Island of New Zealand. It is part of New Zealand's s ...

, tāngata whenua and other agencies.

Biodiversity

In the summer of 2021 to 2022, an

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

survey was undertaken by Julia Palmer and a total of 175 different invertebrate species were found to inhabit the Charlesworth Reserve in the Avon-Heathcote Estuary/Ihutai.

References

Literature

* {{Authority control Rivers of Christchurch Estuaries of New Zealand Wetlands of Canterbury, New Zealand