The Ōpāwaho Heathcote River extends for approximately 25.5 km from south-west Christchurch to its mouth at Te Ihutai (Estuary of the Ōtākaro Avon and Ōpāwaho Heathcote Rivers) in Ferrymead. The catchment covers approximately 103 km² in the south of the city stretching north to south from the edge of the Central Business District to the top of the Port Hills and west to east from Ruapuna Park to the Ihutai Avon-Heathcote Estuary.
Christchurch was once a mosaic of wetlands and small waterways formed by the past actions of the Waimakariri River and its underground aquifers. The river passed through habitat that was abundant in flax (harakeke), toetoe, raupo, tutu and ferns and was dotted with ti kouka (cabbage tree). The river corridor is low-lying and was historially very wet.
The wetlands draining the Ōpāwaho Heathcote River were called Te Kuru and the upper reaches of the river at Spreydon was called Wai Mokihi after a smaller pā located there called Ō Mokihi, which means meeting place of the raupo rafts. Waitaha people would have known the Ōpāwaho river area first, and then came Kati Mamoe and Ngāi Tahu.
Ō-pā-waho means Outpost pā. It refers to a pā sited just downstream of the present Opawa Road Bridge at what is now the intersection of Judges St and Vincent Place. The Ōpāwaho pā was used by Ngāi Tahu, who used the Ōpāwaho River to travel between Tuahiwi, Kaiapoi and Te Pātaka o Rakaihautu (Banks Peninsula). Water plays a unique role in the traditional economy and culture of Ngāi Tahu. The most direct physical relationship that Ngāi Tahu have with water involves the protection, harvesting, and management of mahinga kai. The term mahinga kai is a broad term that refers to natural resources, particularly the way resources are gathered, the places they are gathered from, and the resources themselves. It includes fish such as tuna and inaka, materials such as harakeke, and paru, which are used for dyes and entire areas such as the Ihutai (estuary) and Orua Paeroa (South New Brighton) and its sand dunes and wetlands.
Near Wigram the Ōpāwaho River is close to the headwaters of the Halswell River. Ngāi Tahu travellers used to drag their waka across this gap, or build provisional moihi from reeds, thus being able to travel by water from Waihora (Lake Ellesmere) to Ōtautahi (Christchurch). The Ōpāwaho River was also an important mahinga kai, a source of plentiful food, especially tuere (blind eel) and kanakana (lamprey) and mata . The swamp forest around the river provided gathering grounds for water fowl and forest birds. Traps were regularly set for inanga (whitebait), pātiki (flounder) and tuna (eels).
In the 1800s Ngāi Tahu made unsuccessful attempts to have some sites in the Christchurch area made into mahinga kai reserves. They were effectively excluded from exercising their kaitiaki responsibilities in the development of the City and the management of the Ihutai catchment.
Longfin and shortfin eels, bullies, kanakana, inanga, kowaro (Canterbury mudfish), kākahi (freshwater mussels), kōura (freshwater crayfish), and pātiki flourished in Christchurch waterways prior to extensive modification by urban development. These were important food sources for Māori, and most are still found in certain parts of the river, but in smaller numbers.
The English name for the river comes from Sir William Heathcote, Secretary of the Canterbury Association, in London. When European settlers arrived, many crossed over the Port Hills at the Bridle Path and made their way down the Heathcote Valley, and crossed the river at several ferry points. The road from here to the settlement was one of the few well-made roads, and is what we know as Ferry Road. Rather than carrying all their goods over the hill, they were shipped around from Lyttelton in smaller vessels (known as a mosquito fleet) which plied up and down the coast . This involved crossing the precarious Sumner Bar without incident, before entering the Estuary and navigating the channels to the Ōpāwaho Heathcote River.
At six to eight metres deep, the river was deeper than the Avon and was important for shipping in the 1850’s. The sharp bends in the river and the wind from the hills and the swamp flats made navigation difficult. A towpath was created on both sides of the river where horses or bullocks were used to tow the boats up the river as far as Richardson Terrace. By the 1860s up to 15 vessels were sailing up the river on a daily basis. It wasn’t a cheap exercise - it would cost almost as much to get goods from Lyttelton to Ferry Road, as it would to freight the same goods from London to Lyttleton! However once the railway to Ferrymead was opened in 1863 and the Lyttelton Railway Tunnel was opened in 1867, the role of the Ōpāwaho Heathcote River in transport diminished greatly.
In 1873 there were seven wool scours and five tanneries on the lower Ōpāwaho Heathcote River; by 1883 there were 11 of each. Subsequently, other industries gravitated to the Woolston area, notably a large gelatine and glue works and a rubber factory. The founding of Para Rubber, followed by the establishment of the Latex, Marathon and Empire factories made Woolston the centre of New Zealand’s rubber industry.
By the1880s the river was too silted to use as a trade route. In the space of just 30 years settlers managed to fill up a water channel that was 8 metres deep. The source of the silt was primarily from the de-forested slopes of the Port Hills, but another contributing factor was that the river was used as a sewer or drain for the industrial factories.By the turn of the 19th Century, nearly a quarter of New Zealand’s industrial activity was located in this area with all their waste being pumped into the river. Stinky!
It wasn’t until 1971 (that’s over 100 years of industrial waste!), when the Woolston industrial sewer was completed, that industrial wastewater was sent to the Christchurch wastewater treatment plant in Bromley instead of running into the river. From a highly polluted, murky and unattractive lower reaches of the river and the Estuary, we now have a much healthier and cleaner river, but there is still a long way to go!