Rakitata River December 2019
The December 2019 flood peaked at 2270 cumecs, with a catchment rainfall of 875mm extending over seven days. As the flood was well beyond the design capacity of infrastructure, the outcome was, unexpectedly, considerable and very costly.
This highlights a key problem that river manager are now facing. NIWA has forecast more frequent and larger floods as the climate changes. All the research points to rivers needing to be given more ‘room to move’ to accommodate these future floods. And yet the High Court ruled that the legal width of a braided river is significantly less than previously defined.
“From the ground, it would have seemed like chaos; floods of water rampaging over the plains, damaging anything in its path. But from above, a different picture was emerging. Environment Canterbury (ECan) staff were photographing the floods from the air, later stitching together the images to create a mosaic of the event.
“It showed the floodwaters were following a predetermined pattern. The flood was itself a river, with twists and braids and tributaries, much like the Rangitata itself.
“A zombie river, long ago buried beneath asphalt and housing and irrigators, had been revived.” – The Rewilding Project / Stuff
Images contains data sourced from the CanterburyMaps and partners licensed for reuse under CC BY 4.0(link is external)