Businesses and homes in The Valley in New Plymouth will get improved protection from flooding with an upgrade to the lower Waiwhakaiho River Flood Control Scheme.
The Waiwhakaiho River Flood Control Scheme is being upgraded by Taranaki Regional Council.
The upgrades by Taranaki Regional Council will raise two sections of the existing defences including along the stopbank and a flood wall which protect shops and houses near Constance Street and Rifle Range Road.
Council Rivers Manager Chris Vicars says revised flood modelling after a large flood event in 2017 identified two sections of the flood control scheme that would require an upgrade.
“While the current defences do provide protection from the design flow of 1180 cubic metres per second or a 1-in-100-year flood, the $450,000 upgrade will provide further protection through allowing for uncertainties associated with climate change prediction and hydraulic modelling,” Mr Vicars says.
“Our mission is to support livelihoods across our region and these improvements will give people living, working and shopping in the area peace of mind that the flood defences can withstand a major weather event.”
The upgrade project is set to be completed by the end of March 2024 and most of the work will take place on the river side of the scheme so will not be visible to the public. There may be some minor traffic disruptions in the area as heavy machinery is moved around the site but that is unlikely to disrupt shoppers heading to The Valley.
“We’re not expecting any major disruptions and action will be taken to minimise noise and prevent dust issues during the work as well. We thank locals, shoppers and businesses in the area for their patience while we complete this vital work to protect the area now and for the future.”
The improvements to the Waiwhakaiho scheme follows an unprecedented year of flooding in New Zealand, with Auckland and Hawke’s Bay residents hit hard by the impact of Cyclone Gabrielle in February.
Fast facts: Flood scheme upgrade
- The upgraded flood defences will be up to 600mm higher in sections
- The upgrade will require approximately 2800m3 of new fill being added to the existing stopbank and concrete capping added to existing flood walls
- The new height is based on achieving the agreed protection standard for the scheme of 1180 cubic metres per second
- This is the estimated 1% AEP or 100-yr flood with allowance for climate change
- The new defences also provide ‘freeboard’ – that means they have an allowance above the modelled flood level to provide for uncertainties.