Descending from New Zealand’s Southern Alps, this ice-blue torrent is known in Maori as the “River of Rapid Cold Water”. In a landscape reminiscent of the Lord of the Rings, it’s still home to some extremely rare flora and fauna. But even at the end of the world, the Waimakariri is classified as one of the most polluted rivers in the country, due to liquid waste from agricultural industries such as meat processing and wool washing…
The Waimakariri is one of New Zealand’s largest braided rivers, and undoubtedly one of its most spectacular. A braided river is a river with numerous unstable channels, forming divisions or connections between these branches. These different arms form a complex network, changing place rapidly and taking on a tangled form reminiscent of a braid.
Because of the outcrops between these perennial arms, braided rivers are true large-scale self-purifying infrastructures and areas of high biodiversity, linked to the diversity of terrestrial and aquatic environments they produce. They provide numerous ecosystem services.
With a catchment area of around 2,500 km2, around 90% of the Waimakariri River’s water rises above its spectacular 25 km-long gorges. Once it leaves the gorge and spreads out over the Canterbury plains, the river loses some of its groundwater to gravelly soils as far north as Christchurch, New Zealand’s second-largest city (pop. 300,000).
The Canterbury area was traditionally arable and livestock farming, but there have been a large number of dairy conversions in the region. In recent years, dairy farming has expanded enormously throughout the South Island. Dairy farming is a water-intensive activity, placing heavy demands on water resources in the Canterbury region.
On the other hand, New Zealand is one of the countries with the most sheep and cows per capita, with 30 million sheep and 5 million cows for 4.7 million inhabitants.
As a result, the rivers of the Canterbury plain are polluted.
And the Waimakariri River is one of the most polluted in the country.
The conversion of land to pasture has resulted in the loss of 70,000 hectares of natural vegetation, decimating part of the biodiversity. 62% of rivers exceed health thresholds due to the dairy industry. And the Waimakariri River is one of the most polluted in the country.
Despite its very high naturalness rate and low population, New Zealand is in fact a country facing a veritable denial of agricultural pollution. 75 animal and plant species have disappeared since the island was colonized by man.
All the island’s flora and fauna are now affected: 90% of seabirds and 84% of reptiles are endangered. New Zealand’s species are among the most threatened in the world.
