Cyclone Gabrielle: One-in-500-year flood prevention system on its way

Hawke’s Bay Regional Council (HBRC) is adopting a one-in-500-year flood strategy for the repair and rebuild of the region’s stopbanks.

The stopbank network suffered 30 breaches during the peak of Cyclone Gabrielle flooding, with several stopbanks also “overtopped” by oncoming water.

An estimated one million cubic metres of fill will be required to bolster the stopbank network, which had been designed to withstand a one-in-100-year flood.

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“This is a major logistical exercise to shift these volumes of dirt, while maintaining quality control,” HBRC asset management group manager Chris Dolley said.

“We have a lot of work ahead of us, but the people of Hawke’s Bay should be confident we are getting on with it as quickly as we can.”

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‘Bunding’ is the temporary measure being employed at the moment by the more than 160 staff undertaking repairs. Put simply, bunding amounts to using mounds of gravel to plug the gaps.

That should see the stopbanks reinstated to pre-cyclone levels, before the real work of upgrading them for the future begins.

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