Te Pā Harakeke project showcases civil engineering working in harmony with nature

Nelson, New Zealand, December 2022: The recently-opened Te Pā Harakeke recreation space at Tahunanui in Nelson demonstrates what can be achieved when civil engineering ingenuity and problem-solving work hand-in-hand with nature.

The project saw a stagnant, algae-dominated pond, known as the Modeller’s Pond, transformed into an engaging and attractive play and recreation area that works with the area’s estuarine environment.

Speaking to guests at the official opening of Te Pā Harakeke, Nelson City Council kaumātua Luke Katu, explained that the the name Te Pā Harakeke was gifted by local iwi and is resonant with meaning as harakeke (flax) grows in whānau lots sheltering the young growth at the centre. The whānau of harakeke is stronger together and the name signals that the area will be a place for whānau. “When the harakeke blossoms so do the whānau,” said Mr Katu.

Nelson Mayor Nick Smith paid tribute to the many people who had contributed to the project, inclduing the Nelson Modellers’ Society, former and current Nelson City councillors and the teams who worked on the project from Taylors Contracting and Nelmac. He also acknowledged key Nelson City Council staff such as Andrew Petheram and Project Manager Rebecca Dawkins.

“We want Nelson to be one of the best places in the world for raising children,” said Mayor Smith. “We want this to be a place of joy for local children and those who come to visit from all around the world and for it to be a place where we enjoy the gift of children.”
Andrew Petheram said that the intention had always been to work with the estuarine environment and that the model train track continued to be operational as the team understood its significance and the place it occupied in the hearts and memories of the community.

Project Manager for Te Pā Harakeke, Rebecca Dawkins, particularly thanked Taylors Contracting for “allowing us to make curvy spaces with ease” and for helping to create a space where animals and humans can thrive together and also acknowledged the contribution of Stantec.
Taylors Contracting’s Nelson Civil Department Manager Robbie Swarbrick said that a number of technical challenges at the site made it a fascinating and complex project at times.

“The main environmental difficulty with this project was dealing with the residue of toxic sludge. Copper sulphate had been used over many years to treat the water to keep it clean however as this became environmentally unacceptable the practice was stopped and the pond was overrun with Ruppia, aquatic weed and algae resulting in a smelly, stinky, pungent pond that was an eyesore.

There was no design instruction provided to us for the disposal of the toxic sludge which remained at the bottom of the pond. Nelson City Council’s environmental policy of “reduce, reuse, recycle” prohibited the sludge being removed from site and disposed of at landfill.

“We came up with the solution of laying locally sourced Lee Valley Limestone “bricks” over the sludge layer. This essentially soaked up the sludge and provided a solid base layer for the subsequent layers of sub soils.

“This also solved the issue of the unpleasant odour which became prevalent after the draining of the pond and which had led to complaints from the community. This solution was also cost-effective and enabled the Nelson City Council to comply with the “no concrete” design brief which local Iwi had requested in order to return the area to a habitat as close to its original form.

“We worked alongside a fish and wildlife ecologist during the draining of the pond. Three-millimetre fish screens previously used at the Waimea Dam site were used to prevent the eggs of invasive species escaping the pond into the estuary.

It took two days to fish the pond and sort the species, with hundreds of eels transferred to new habitats. The Department of Conservation was on hand to provide euthanasia treatments for the invasive species. Records of relocated species were kept and Stantec Engineers recorded water samples hourly while the fishing process was undertaken.

The weather also played a part in the project, says Robbie, including providing an unexpected benefit.

“When we couldn’t get the supply of sand needed to meet design specifications within the allowed budget, onsite managers and council representatives came up with the solution to excavate the sand which had accumulated from a storm surge in the Tahunanui back beach carpark. This was a real win:win – providing free maintenance on council reserves and reducing the cartage of sand which was readily and freely available locally.

“The Taylors team are really proud of the way the project has turned out and it’s great to see that visitors to Te Pā Harakeke can even read an information panel at the site about one of the solutions that our team put in place to discharge clean stormwater into the Waimea Estuary via a earth bunded swale.

It’s children, however, that will have the final say on whether the design will meet the brief at Te Pā Harakeke. If the immediate reaction from on opening day is anything to go by, the new community facility will be a huge hit with young visitors. It’s already garnered five-star reviews online and children at the official opening were reacting joyfully to the spaces to play and areas to ride their bikes. Mayor Smith was even spotted boulder hopping in a game of chase with one young visitor.

Te Pā Harakeke is clearly not only a place for children but also for the young at heart.