Source: ABC News: Cason Ho
A closed-door risk review has set new alarm bells ringing over the future of Perth’s drinking water, with engineering giant GHD recommending that bauxite mining expansion by Alcoa poses risks to the safety of water abstracted from key metropolitan dams.
The report, prepared at the behest of the state-owned Water Corporation, identifies 22 possible avenues of contamination linked to the mine project. With 21 rated as “high risk”, from hydrocarbon spills to run-off from sediment, the threats loom as a terrifying prospect: in a worst-case scenario, the risks could swamp treatment facilities at Serpentine and Pipehead dams—critical sources providing nearly half of Perth’s two million residents.
The risk is clear: if serious pollution takes hold, the cost of maintaining Perth taps clean may be up to $3.25 billion, with residents potentially subject to boil-water notices or dependence on bottled water.
What the GHD Report Revealed
Research discovers a roll call of threats if left unchecked, would transform Alcoa’s expansion a industrial success into an epidemic of public health:
Hydrocarbon pollution: Motor vehicle and machinery oil and diesel spills can potentially enter dam catchments.
Soil erosion: Expanded Jarrah forest clearing has the capacity to destabilise slopes, causing sediment clogging of reservoirs and damaging filtration systems.
Pathogen invasion: Extremely infrequent but “catastrophic” invasions could take place whereby pathogens invade the supply, forcing treatment systems to run beyond safe levels.
The discovery fuels years-old concerns that Alcoa’s mining presence—already extensive in the Darling Range—is too close to Perth’s water catchments. Conservationists point to over 220 square kilometres of jarrah forest having been cleared over decades, with minimal rehabilitation up until now.
WaterCorp Sounds the Alarm
Source: ABC News
The city’s private water utility, the Water Corporation, quietly confirmed the extent of the threat. In internal board documents, the utility threatened that contamination would result in emergency subsidies for bottled water to over 100,000 citizens.
One report succinctly described the situation as a nightmare for the company’s reputation:
“A boil-water notice could be issued within hours, and the stakes in public trust would be astronomical.“
The intensity of those concerns resulted in WaterCorp withdrawing from a government advisory board on mine approval decisions, allegedly concerned that its integrity would be at risk if it were implicated as complicit in the approval of such a clearly contentious project.
Alcoa Pushes Back
Alcoa, which has been mining in Western Australia for sixty years, denies its mining is a threat to the water supply of Perth. The company cites a six-decade history of no proven contamination and claims that its activities are strictly regulated.
The aluminium giant claims to no longer mine in officially declared reservoir protection areas and has spent millions on new drainage systems, groundwater monitoring bores, and PFAS treatment technologies.
Company spokesman Harold Dettmann stated:
“Alcoa has an impeccable record of defending Perth’s water supply and is committed to co-operating with regulators to maintain community confidence.”
But green activists are wary, noting that earlier pollution sprees caused by PFAS and other chemicals only subsided when the outcry from the public called for it.
The Bigger Picture—Why It Matters
It is not just a matter of one smelter or a single mine. It is at the center of Western Australia’s balancing act: how to keep vital public assets intact and yet have industries that keep the state economy running.
Bauxite and alumina production are still staples of WA’s export basket, generating thousands of jobs and billions of dollars in revenue. But as GHD’s report hints, the price of poor planning may prove to be a whole lot larger than the dividend.
Critics accuse this of being an old story of short-term economic benefit against long-term community resilience. Once a water supply is jeopardized, they argue, no royalties or export revenue will ever make up for damage to health, trust, and the environment.
Climate Pressures Amplify the Threats
The risk is further added to by global warming. Perth’s rainfall has decreased by almost 60 per cent since the 1970s, rendering dams more vulnerable to pollution because reduced inflows equate to less natural dilution.
As described by one hydrologist:
“A big rain used to wash through the system of pollutants. Now, with the dwindling inflows, the same pollutants hang around and build up.”
This climate reality leaves the jarrah catchments more exposed than ever before, questioning whether or not to proceed with mining near dams at all.
Political Fallout
The report from GHD has set off a political storm already. Opposition MPs are demanding an independent inquiry, but ministers from the government promise that the Environmental Protection Authority (EPA) will provide a stern evaluation before approvals can be made.
Premier Roger Cook sought to assure that water security is “non-negotiable” and WA would not compromise the safety of Perth residents.
But others claim the Government is walking a tightrope, struggling with the desire to safeguard an international mining behemoth and growing expressed concern from local communities.
Communities Speak Out
Source: ABC News: Andrew O’Connor
For residents who live in the shadow of Alcoa, the dangers are far from hypothetical. Residents in Dwellingup and Jarrahdale towns already have clearing, truck noise, and dust to contend with. Now they fear their drinking water is on the list.
A local activist described the mood as “a fight for survival”:
“If the water goes, the community goes. It’s that simple.”
What Happens Next
The Environmental Protection Authority will consider Alcoa‘s expansion plan next year. Local community activist groups are planning a deluge of submissions, while WaterCorp is secretly modeling scenarios for multi-billion-dollar treatment upgrades.
If the water is contaminated, taxpayers would pay the price. For some, the issue is whether the government acts now—or waits until an emergency forces its hand.
The Bottom Line
Alcoa’s bauxite expansion is proving to be a proving ground for WA’s capacity to handle resources. The state has to balance economic development and environmental sustainability with trust in the people. As the GHD report makes starkly obvious, the dangers are not theoretical—tangible, quantifiable, and expensive. Perth’s water future might depend less on engineering legerdemain than political will to put a line in the jarrah forest.
