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https://www.theguardian.com/world/ng-interactive/2026/may/07/tame-the-water-or-let-it-flow-new-zealand-grapples-with-how-to-protect-its-braided-rivers>
"When British settlers started building Christchurch city 170 years ago, they
largely ignored the nearby Waimakariri River, which twists from the South
Island’s alps towards the eastern shore.
But rain and glacial shifts compelled the braided river – a globally rare form
of river with many woven channels – to take on a new shape, occasionally
flooding land and depositing tonnes of shingle in its wake.
By the 1920s, the Waimakariri was described as a “flood menace” in a report to
authorities, one that showed a “deficiency of nature, which must be made good
by the art of man”.
With that, the river was brought into submission, slowly hemmed in with
stopbanks, exotic tree planting and gravel extraction. Now it requires endless
maintenance to tame the river and prevent the risks of flooding to homes,
infrastructure and the nearby airport.
“People say you shouldn’t be interfering with the river; the outcome if we
don’t is worse,” Fred Brooks, a river engineer with the local regional council,
Environment Canterbury, says.
“It has been intervened in so much at this point, you have to keep
intervening.”
The Waimakariri is one of about 150 braided rivers across New Zealand, 60% of
which are concentrated in the South Island’s Canterbury region. The unique
river systems are found in just a handful of other places around the world,
including Alaska, Canada and the Himalayas.
These systems face – and also pose – a complex set of challenges. They have
been disrupted to make room for farming and allow communities to develop, but
those changes are damaging ecosystems and species, affecting water quality and
exposing communities to flood risk.
Concerns are growing over the future and resilience of braided rivers,
prompting questions over how the country can live alongside them while
preventing their further decline.
“Braided rivers are iconic – we use their iconography all over the place,” says
Jo Hoyle, a river geomorphologist at Earth Sciences New Zealand. “And yet, are
we really looking after them?”"
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
