New flood wall to protect Whangārei CBD properties along Wood Rd

Northland Regional councillor Jack Craw, left, and rivers and natural hazards manager Joseph Camuso holding a photo of floods 20 years ago. Photo / Supplied

A new 113m-long flood wall is expected to increase the level of flood protection for several properties near the Whangārei CBD.

The Woods Rd flood wall is part of a wider flood mitigation programme the Northland Regional Council is rolling out under its Long-term Plan 2018-28 and will help protect flood-prone land along Raumanga Stream.

Regional council natural hazards manager Joseph Camuso said contractors Barfoote Construction built the flood wall in about 10 weeks at a cost of $360,000.

"Now it's finished, we've effectively given Commerce St one-in-50-year flood protection, a big improvement on the previous one-in-10-year protection," he said.

"This is the first place in the city that the Raumanga Stream overflows during a flood."

The one-in-50-year flood is a rating system to describe the probability of a flood of a certain size occurring in any river.

The new wall was installed along the riverbank between Railway Rd and Woods Rd protecting two larger properties.

Floodwaters typically flow down Commerce St, flooding low-lying properties before flowing back into the river before Okara Dr.

After ex-tropical Cyclone Wilma in January 2011, some cars parked along Woods Rd were inundated with floodwater that reached as high as their rear-vision mirrors.

"The amount of rain that actually falls in any given year can vary tremendously and no one has any control over that, but, in theory, these works should cope with the sort of rainfall you'd normally expect to occur up to once only every 50 years," councillor Jack Craw, recently appointed chairman of the Whangārei Urban Rivers Flood Working Group, said.

The recently completed project is part of the Whangārei Urban Rivers Flood Mitigation Project which started in 2009.

The recent project targets about $1m in flood mitigation works during the next three years.

As proposed, 70 per cent of that work would be funded by ratepayers Northland-wide via the council's regional flood infrastructure rate, with the balance funded locally through a targeted river management rate.