The potential for an employment area was identified by the state government more than 20 years ago.

The first chunk rezoned, some 500 metres away from the wetland, is now the $450 million Roe Highway Logistics Park – sitting on about 73 hectares of land – owned by Fiveight, Hesperia and Gibb Group.

Linc Group, which is now part of Hesperia, bought up rural land from two dozen property owners for $120 million to create the logistics park which is just 5 kilometres from the Perth airport and is close to the industrial suburbs of Kewdale and Welshpool.

The next two stages of the Maddington-Kenswick Strategic Employment Area are more contentious and border the wetlands.

They were referred to the EPA in 2017 but will now be examined along with an interchange upgrade of the Tonkin Highway, and the rezoning of 125 hectares of land south of Wattle Grove from rural to residential with 80 private lots in the City of Kalamunda.

EPA chairman Matthew Tonts, who started in the role last year and is a professor of geography at UWA, said the level of biodiversity in the wetlands was something akin to the Fitzgerald River National Park in the state’s south, one of Australia’s biggest protection areas and nearly 3000 square kilometres in size.

“It’s a really, really important area but what you’ve also got is a proposal for industrial development on both sides of this and then housing development,” he said.

“What we’re interested in is, well, if you put a housing development in over this area here, and you’ve got groundwater recharge happening, and the groundwater flows are in this direction, down to the Canning River, what does it mean for this little gem?”

“So we’ll look at the floristic communities, we’ll look at groundwater attributes and so forth and ... the objective then is to understand that particular site a little bit better, but also then provide some guidance to developers, to decision makers and potentially to the minister [Reece Whitby] about enhancing environmental protection for that site.”

All about the water

The EPA has previously estimated that about 80 per cent of the wetlands on the Swan Coastal Plain – a 30-kilometre wide strip between the Darling Scarp and the Indian Ocean running from Cape Naturaliste to north of Perth – have been lost or irreversibly degraded.

The Greater Brixton Street Wetlands rely on the shallow layer of a multi-level aquifer below it which runs 3000 metres deep and includes the Jandakot Mound, the smaller of Perth’s two aquifers used for drinking and private water use.

The aquifer needs rainwater to recharge which means wetlands are at-risk of drying out, like many north of the Swan River on top of the Gnangara groundwater system, if the underground source is being depleted faster than it can fill up.

UWA Emeritus Professor Hans Lambers wrote in his book about the proposed Yule Brook Regional Park, A Jewel in the Crown of a Global Biodiversity, that industrial development around Perth’s remaining wetlands must be managed carefully for their conservation so recharge was not impacted.

Lambers told WAtoday he hoped the EPA’s process would ensure an area that was immensely biodiverse on a global scale would be protected through the establishment of a regional park.

“The Beeliar Group that proposed such a regional park is not against development, but insists such development must occur with full respect of the fragility of a megadiverse and vulnerable environment,” he said.

“Developers have the tendency to carve out small parcels of a large region, and claim the impact of their plans on the environment is negligible, thus ensuring death by a thousand cuts.

“That strategy leads to sacrificing a globally important region that should be looked after for posterity and be showcased for the purpose of education and ecotourism.”

When it comes to development around the wetlands, City of Gosnells acting chief executive Chris Terelinck said there were two main objectives.

“Firstly, the aim is to have no impact on the wetlands, and to facilitate its continued natural function,” he said.

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“Secondly, the wetlands should gain further protection than has historically been the case, by the removal of ad-hoc clearing and unregulated activities that previously bordered the wetlands area.”

Terelinck said previous development in the Maddington Kenwick Strategic Employment Area had demonstrated industrial development could co-exist with the wetlands.

“These early stages include elements that complement natural environmental values, such as leading edge drainage design and stormwater quality management, revegetation and renewal of food sources for black cockatoos, and the introduction of award-winning and sustainable construction technologies,” he said.

EPA to look more broadly when assessing Perth projects

Understanding the cumulative impact of multiple projects instead of individual ones which come to the EPA is a goal of the authority under Tonts.

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He said going forward the watchdog would be keeping its eye out for particular locations or environmental contexts requiring protection.

“One of the places we’re having cumulative impacts at an extraordinary rate is on the Swan Coastal Plain and so I think ... that’s got to be an area of focus,” Tonts said.

“The challenge for the EPA is that we’re often ... having to assess often at this very, very micro scale, when in fact, we know that we need to consider things at a much more landscape scale if we’re to have really significant environmental protection outcomes.

“If we continue to go down the road of just assessing piece by piece parcels of land, we have to ask ourselves, will we be achieving good environmental outcomes?”

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