A quarry company seeking to take over a section of Belmont Regional Park is confident it's offering a like-for-like land swap, despite protests from local advocates.
The Friends of Belmont Regional Park say there are irreplaceable trees within the boundary, with recent ecological surveys discovering swamp maire and ramarama, in addition to a natural wetland.
Quarry company Winstone Aggregates, which is owned by Fletcher Building, is trying to acquire a block of land adjacent to the quarry, 24 hectares in size, and within the regional park which sits between the Hutt Valley and Kāpiti Coast.
Owned by the Department of Conservation and maintained by the Greater Wellington Regional Council, it is currently covered in native bush - some regenerating farmland, other parts original growth.
Winstone Aggregates general manager Amanda Croft explained there were two parts to the process - first they were seeking DOC's support for the swap in the form of a report, which would then be attached to their application for consent under the Fast-track Approvals Act.
The project had already been named as a listed project, but final sign-off would come from an expert panel.
If successful, the land would be used as a dumping site for the by-product known as overburden, the layer of soil covering the hard rock needed to make aggregate.
The quarry supplied 40 percent of the total aggregates needed in the Wellington region, used to make concrete for roads and housing.
Croft said minimising the distance things needed to be transported reduced costs, emissions, and wear and tear on the roads.
Their proposal was to swap out the 24-hectare block of DOC land for three blocks of quarry land totalling 30 hectares - a net gain for the regional park when it came quantity.
But as Croft explained, it was also about quality.
"This is of high ecological value," she said. "We've had the experts out testing, working through how we qualify the value of it, then we can make sure we're swapping a better version than what we're taking."
Standing in front of a patch of regenerating bush, she gestured to a previous overburden site, which had been replanted some years back and was now returning to something close to its original state.
"Part of what we do is always making sure we return things to the way they've come from," she said.
"Once we've done the quarrying, we move silts and clays into an area, we form it up, and we use experts to make sure [...] we return it into native species and a land form that works with the environment around it."
Recently, the boundary of the land swap had changed. Originally 29 hectares of regional park would have been traded for 31 hectares of Winstone's land - both covered in bush.
But following ecological assessments, Croft said, the boundaries had changed, and now, 30 hectares of Winstone land would be traded for 24 hectares of regional park.
"We've had experts out here for the last few months," Croft explained. "They go through a very complex process where they evaluate the land, the species, the trees, the age, to come up with the ecological value."
Project manager Phil Heffernan said feedback from the community had led to some areas being removed from the swap.
"Things like the swamp maire came through pretty strongly, both from the community and our ecologists," he said.
A big chunk of the Dry Creek area around the car park had also been removed, after feedback from the community and local iwi that it would not add any ecological value.
But advocates for the park are questioning why any part of the native bush needed to be impacted.
Jonathan Ravens, a member of the Friends of Belmont Regional Park who had been championing its protection, said more rare plants - including whekī (tree fern), ramarama and swamp maire - had recently been found within the land swap boundary.
Ramarama and swamp maire were both susceptible to myrtle rust, adding that extra layer of vulnerability to their already threatened status.
Standing in one of the valleys, light filtering through the green leaves and the sounds of nearby suburbia well obscured, Ravens gestured around him.
"If this is all filled with rock, way above our heads now, and then replanted, then there would be no wetland, all the original vegetation would be lost, there would be no swamp maire," he said.
"In maybe 50 to 100 years it would start being a nice place to be, but it wouldn't be as nice as this by a long chalk, and the original trees would be lost forever."
He said previous ecological surveys had under-represented the rare fauna within the boundary - and he hoped more recent surveys, plus information they were sharing with DOC, would prove the site too valuable to fill in.
"What we can do is keep on wandering through here, seeing what there is, ground-truthing," he said.
"And also keeping the public perception aware, because the fast-track part, and the land swap, aren't actually public consultations.
"But we can keep it in the public eye, so that everybody knows that everybody's watching."
Siobhan Quayle, DOC's director of regulatory systems performance, said they had not yet received an application from Winstone's, but they had been in discussions about a land swap on two separate occasions - first in 2017, and again in 2022.
The department would be providing a report which the quarry would then lodge along with their application under the fast-track process, but they were not decision makers.
"While DOC will provide advice to the panel during the substantive application phase, it is ultimately the panel's decision."