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” refers to natural resources and the area in which they are found. It includes the way resources are gathered, the places they are gathered from, and the resources themselves, for example, fish such as tuna and inaka, materials such as harakeke, and paru, which are used for dyes.
Waitaha people would have known the Ōpāwaho river area first, and then came Kati Mamoe and, later, 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 to travel between Tuahiwi, Kaiapoi and Te Pātaka o Rakaihautu (Banks Peninsula).
The wetlands draining the Ōpāwaho 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 meaning place of the flax-staff rafts.
Near Wigram the Ōpāwaho is close to the headwaters of the Halswell River. Ngāi Tahu travellers used to drag their canoes across this gap, thus being able to travel by water from Waihora (Lake Ellesmere) to Otautahi (Christchurch).
The Ōpāwaho was an important mahinga kai, a source of plentiful food, especially tuere (blind eel) and kanakana (lamprey). The swamp forest around the river provided gathering grounds for water fowl and forest birds. Traps were regularly set for inanga, pātiki and tuna.
In the 1800s Ngāi Tahu made unsuccessful attempts to have some sites in the Christchurch area made into mahinga kai reserves, and were effectively excluded from exercising their kaitiaki responsibilities in the development of the City and the management of the Ihutai catchment.
The English name for the river comes from Sir William Heathcote, secretary of the Canterbury Association. The Ōpāwaho Heathcote river was important for shipping in the 1850’s. At six to eight meters deep, the river was deeper than the Avon. There was enough water that boats sailed all the way up from the estuary up Ferry Road, carrying goods from Lyttleton. The sharp bends in the river and the wind from the hills and the swamp flats made navigating difficult and a towpath was created on both sides. Some of the bends and strong current made navigating the river tricky, so horses or bullocks were needed to tow the boats up the river as far as Richardson terrace.
The lower Ōpāwaho Heathcote became a major traffic artery - by the 1860s up to 15 vessels were sailing up the river in one day. It wasn’t a cheap exercise - it would cost almost as much to get goods from Lyttleton 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 Heathcote/Ōpāwaho in transport diminished greatly. By the 1880s 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 meters deep. The source of the silt was primarily from the de-forested slopes of the Port Hills.
From the late 1800s onwards the Woolston Loop in the lower Ōpāwaho Heathcote was used as a drain for industries including tanneries, wool scourers, a flax mill, a glue works, soap and candle works, an abattoir, a leather-goods manufacturer and a carpet factory. By the turn of the 19th Century, nearly a quarter of New Zealand’s industrial activity was located in this area. Industrial waste was pumped into the river, making the water highly polluted, murky and unattractive for decades.
Trout were naturalised in the Ōpāwaho Heathcote in the 1860's.
The river was used as an industrial drain until 1971, when the Woolston industrial sewer was completed. After this, industrial wastewater was sent to the Christchurch wastewater treatment plant in Bromley instead of running into the river. This has improved the health of the lower reaches of the river and the Estuary.