Man-made riverbanks prevent us from being washed away and it is the Hawke's Bay Regional Council's job to keep the flood-control measures intact.
But river gravel - as it rolls down from the mountains - can pile up, making the many man-made stop banks less effective as the levels of riverbeds rise.
Luckily river gravel is a valuable resource for construction projects, so it has been a win-win for Hawke's Bay because of industry extraction.
But in Central Hawke's Bay, supply far exceeds demand.
"It has always been a bit challenging to encourage industry to take material from the Upper Tukituki River," Hawke's Bay Regional Council asset management group manager Chris Dolley said.
"We've discounted the removal of material from the Upper Tukituki Scheme down to 20 cents a cubic metre.
"The charges we impose are around the Regional Council managing the resource – it is not a profit-making charge - and we've also been working through a new consent that would give us greater flexibility to direct where the material is taken from.
"So we have been trying, but it has been challenging because of the additional costs and some of the locations of the major projects in Hawke's Bay."
So when central government said it was looking for ways to help the construction industry post-Covid, Hawke's Bay Regional Council presented a timely business case through the Infrastructure Reference Group (IRG), a Government advisory group.
"We were very much looking for recovery opportunities for New Zealand," Dolley said.
"The river managers across New Zealand put up a $300 million programme, that was funded under the Covid recovery programme from central government, and $30 million of those projects are occurring in Hawke's Bay.
"The Upper Tukituki is one of those, valued at around $8 million.
"Central government is paying 64 per cent of those costs and we need a contribution from the scheme of 36 per cent."
Flood-control measures cover a large swathe of Hawke's Bay, from the Upper Tukituki's five rivers to the Heretaunga Plain's big three.
Dolley said without the flood-control measures, Hawke's Bay would suffer.
"The Heretaunga Plains would effectively flood quite frequently and we would see damage to buildings, to property, interruptions to transport corridors and it would be quite a different place to what we have today.
"It protects a huge industry, in terms of farming and horticulture, and many towns as well.
"The Upper Tukituki is also protecting the towns of Waipawa and Waipukurau.
"So it's very important, to ensure our community is resilient. Not only to the current challenges but future challenges of climate change as well."
While there's no shortage of quantity, the Regional Council has also assured the river-gravel's quality, sharing testing data with industry.