Big Dig Followed By Big Planting


The Northland community of Mangawhai is famous for an extraordinary commitment to its harbour – and that is continuing, thanks to the Fonterra Grass Roots Fund.

The Northland community of Mangawhai is famous for an extraordinary commitment to its harbour – and that is continuing, thanks to the Fonterra Grass Roots Fund.

Back in the 1990s Mangawhai residents defied authority, turning out with diggers to repair the sandspit shielding their historic waterway.

Today the Fonterra Grass Roots Fund is backing a less dramatic but equally commendable project aiming to enhance the water of the Mangawhai Harbour. The Mangawhai Riparian Planting Group plans to improve water quality by planting the banks of streams running into it. 

"At present heavy rain turns the harbour from crystal blue to earthy brown," says a spokesperson for the group, Belinda Vernon. “Though it’s early days, volunteers have begun working with sympathetic farmers and other land owners to plant out stream banks to prevent excess run-off of this type.”

“It’s a long term project as, over the years, the bush around streams has been cleared as many areas of land have been cleared for development.”.

“As a result, there is a constant run-off from land into the harbour. Many farmers and individuals are doing their bit by planting along the sides of streams – but there is a lot of work to do. We’ve had our problems – with stock getting into the planting site and chewing the plants. We learnt the hard way the importance of good fencing.”

It's the latest evidence of a unique commitment Mangawhai people have to the harbour popular with thousands of boaties, fishers, bird watchers and holidaymakers.

The harbour wasn't always such a pretty sight. Back in 1991, the sandspit was collapsing due to sand dredging and storm damage.  The harbour entrance was blocked up and the spit had an unwanted breach to the south.

Unable to flush-out with the tide, the harbour became dangerous for boaties.  Stagnating water threatened marine life. Flooding caused by erosion to the spit was wiping out nests of migratory birds.

The authorities claimed the damage was from a natural event, so had to be accepted as the status quo. Direct action to rectify the situation was forbidden.

At 6am on February 11, 1991, digger and truck drivers from throughout Northland turned up on at the sandspit with their machines to open the blocked channel and close the southern breach.

The Big Dig was an important opening gambit of the Mangawhai Harbour Restoration Society. It woke the authorities up to the need to save the harbour from imminent ecological collapse. Locals purchased a sand dredge with community funds and the Director-General of Conservation approved placing dredged sand back onto the spit. A skilled coastal engineer took over the design and work began on shifting a staggering 268,000 cubic metres of sand.

Volunteers put in thousands of hours constructing rock groynes, plus fences to stabilise the bund wall defining the harbour. They also planted 100,000-plus pingao and spinifex plants — grown in local nurseries — to stabilise sandhills, a job continuing to this day.

The Big Dig was just the beginning of the ongoing operations of the Mangawhai Harbour Restoration Society, which remains active. The Mangawhai Riparian Planting Group's plans demonstrate that local desire to protect their harbour is strong as ever – and Vernon says they are delighted that Fonterra has come to help.