In 1968, a Māori elder named Hikaia Amohia stood up at a public meeting in Taumarunui, a town beside New Zealand's Whanganui River. The government planned to divert water from the river's headwaters for electricity. Amohia asked the Minister of Electricity why his people had never been consulted.

The chairman ruled him out of order. The question went unanswered.

Water began leaving the headwaters three years later, passing through a hydroelectric scheme towards Lake Taupō. Parts of a tributary ran dry. Nearly half a century after the meeting, New Zealand passed a law recognising the Whanganui River as a legal person, with people appointed to act on its behalf.

The Tongariro Power Scheme is still diverting water. What, then, can a river's legal personality actually do?

The Whanganui flows from the volcanic mountains of the North Island towards the Tasman Sea. Along its banks, generations of Whanganui iwi, the Māori tribal communities connected with the river, have drawn food from its waters and travelled between settlements. The river is also understood as an ancestor, Te Awa Tupua. Its many tributaries belong to the same living whole, and particular communities have responsibilities towards the places they know. The relationship is expressed in the words Ko au te awa, ko te awa ko au: I am the river, and the river is me.

In the nineteenth century, the colonial government saw another possibility in the river. Steamboats could carry people and goods farther inland, provided they could get through the rapids. Crews began clearing stones and removing structures that stood in the way.

Among them were wooden fish traps called weirs. They were built to catch migrating eels, and their design depended on the current. A long, sturdy fence ran almost parallel to the water near the top of a rapid, guiding the fish into a net at one end. The fence had to survive floods capable of carrying heavy logs downstream. Some weirs had their own names and histories. Families maintained them, and the catch helped sustain communities through winter.

The navigation crews treated the weirs as obstructions. By 1891, a government engineer reported that most had been destroyed. Some were rebuilt. People petitioned Parliament, asking for their fisheries to be protected.

In 1895, Mereaina Rauangina and 151 other Whanganui women described what had happened when stones were taken from the river. Fishing places had dried up. Banks were eroding, carrying away land used for homes and cultivation. The works had altered the water in ways that people living beside it could see.

Government authority extended beyond the navigation crews. A court had already refused, in 1871, to investigate Māori interests in the riverbed below the high-water mark. Subsequent legislation vested the beds of navigable rivers in the Crown. Whanganui iwi kept petitioning and challenging the Crown's decisions.

One of the people who carried that argument into court was Titi Tihu. When proceedings over the riverbed began in 1938, he composed a waiata, a song, whose opening places him at the doorway of his house, listening to the wind. He turns his thoughts towards the rippling waters of Whanganui and the responsibility of speaking for his people before the Crown. His words survive in the settlement record.

The case lasted 24 years. Earlier rulings recognised the customary interests of Whanganui iwi. The final judgment turned on an English legal presumption about ownership of land beside rivers.

Under that presumption, a landowner's rights may extend from the bank to the midpoint of the riverbed. In 1962, the Court of Appeal held that the granting of titles to land along the Whanganui had extinguished Māori customary ownership of its bed.

The line existed only in law, running down the middle of moving water. Whanganui iwi had been required to argue about the ground beneath a river they understood as a living ancestor.

Meanwhile, the power scheme went ahead. From 1971, water from the upper Whanganui catchment was carried into the Waikato system. Between 1975 and 1977, roughly 84 per cent of the mean flow of the Whanganui's headwaters was diverted. That figure describes those years, rather than the river's flow today.

The 2014 settlement deed estimated that the diverted water contributed about 5 per cent of New Zealand's electricity, including generation farther downstream. The Crown later acknowledged that its failure to consult Whanganui iwi had breached the Treaty of Waitangi and that the diversion had harmed their cultural and spiritual values.

Tihu died in 1988, before another hearing about the river's flows. Amohia continued speaking for the river. At the Planning Tribunal appeal that followed, he said that interfering with its flow meant interfering with nature itself.

A Waitangi Tribunal report in 1999 found that Whanganui iwi had held rangatiratanga, their authority over the river, and had never sold those interests. The Crown had failed to protect that authority. Negotiations followed, with a difficult question at their centre: what form of recognition could accommodate a river understood by its people as an ancestor?

Transferring the riverbed to Whanganui iwi would still have treated the river as property held by somebody else. Negotiators turned to a legal device already used throughout modern commerce.

A company is a legal person. It can hold property and be taken to court, even though nobody imagines it is human. Genesis Energy, which operates the Tongariro scheme, is one such company. The river could have legal personality too.

The Crown and Whanganui iwi signed a settlement in 2014. When the legislation passed its final reading in March 2017, more than 200 descendants of Whanganui iwi were watching from Parliament's gallery. They sang after the vote.

The law recognised Te Awa Tupua as a legal person. It vested Crown-owned parts of the riverbed in the river itself and established Te Pou Tupua, two representatives required to act in the river's interests. One is nominated by iwi with interests in the river, the other on behalf of the Crown. Some public decision-makers must now recognise and provide for the river's status and values. Others must give them particular regard when exercising specified powers.

Section 46 of the Act draws another line, between the riverbed and the water. Vesting the bed in Te Awa Tupua gives the river no ownership rights over the water flowing above it. Te Pou Tupua's consent is not automatically required when someone seeks to take or divert that water. A consent authority may, however, determine that Te Pou Tupua is an affected person in a resource-consent application relating to water.

The question Amohia was prevented from asking had finally entered the machinery of government.

Some of the institutions established through the settlement take their names from the old fishery. Te Pā Auroa recalls the broad eel weir built to withstand seasonal floods. Te Kōpuka refers to the white mānuka used to build it. A river strategy called Te Heke Ngahuru takes its name from the first autumn migration of eels, once an important source of winter food.

Far upstream, water from the Whanganui still enters the Tongariro scheme and travels through canals and tunnels towards Lake Taupō. The principal consents authorising those diversions expire on 1 December 2039.

Sources and further reading