Rotting Blenheim boardwalk could be replaced with synthetic boards

Rotting wooden boards at Blenheim’s Riverside Park may be replaced with a new synthetic product that has only just reached the New Zealand market.

The boardwalk, on both sides of the Taylor River, was built as part of a wider realignment of State Highway 1 in 2001.

But the area is often underwater during flooding or when the river’s water levels remained high.

Parks and open spaces officer Robert Hutchinson told the council at a long-term plan budget meeting on February 26 that the macrocarpa decking was not surviving the damp conditions.

“Riverside Park is connected to The Quays, and also in some way connected to the library, and provides access to and from the town centre, and other areas in the town, including the quite successful Taylor River walkway.

“Sitting underneath the macrocarpa is a build up of silt that's happened over the years.”

Several boards had become rotten and had been replaced since 2015. The council had spent nearly $90,000 on repairs to the area since 2016, of which $27,000 was spent in this financial year.

Hutchinson said they wanted to replace the macrocarpa with synthetic, recycled plastic after they investigated available options in the market.

The electrical system and lights on the boardwalk had also deteriorated and needed replacing.

He said the synthetic boards were “big in Australia” and had just started to make their way onto the New Zealand market.

“It is the same price as replacing the macrocarpa decking, we got a very good price from the supplier.

“I think it's a matter of having a big project that they want the product to be in ... [in] New Zealand, and then can use it within their promotional preview of the material.”

The product had an 80-year life, compared to the short life of 10 to 15 years for the macrocarpa.

Full replacement of the boards was budgeted at $286,400 and the electrical work was $207,200, bringing the total to nearly $500,000.

Wairau-Awatere councillor Gerald Hope asked if the product was “non-slip”.

Marlborough mayor Nadine Taylor said she had a similar question and asked if it had been “well-tested” given the council had dealt with issues with slippery tiles in the past.

In 2019, the council “scuffed up” the pavers in Blenheim to make them "slip resistant", following reports of injuries.

Hutchinson confirmed the plastic boards had been well tested in Australia and they had tread on them to help with grip.

“And hopefully that will save us from putting frost grip down onto the existing wooden decking in the winter months when it gets too frosty and too wet.”

Under the long term plan, the council also had plans to dredge the Taylor and Ōpaoa rivers at a cost of $800,000 which was hoped to help prevent flooding.

The council voted in favour of the proposal which would go out for consultation under the Long Term Plan 2024/2034 from April 4 to May 6.

LDR is local body journalism co-funded by RNZ and NZ On Air.