The Big Australian is certain that extracting an additional 29 Optus Stadiums worth of groundwater from the Pilbara each year will have “no impact” on water supply for WA residents.
BHP last week applied for permission from the Department of Water and Environmental Regulation to draw a further 29.2 million kilolitres of water a year from two separate aquifers.
If accepted, it’ll almost double the miner’s permittable water extraction limit to 65.7 million kilolitres per year — enough water to fill WA’s premier stadium to the brim nearly 66 times over. This also equates to filling up about 26,280 Olympic-sized swimming pools.
WA is heavily reliant on groundwater, with about 78 per cent of all potable water across the State drawn from underground aquifers.
Miners consume the lion’s share, responsible for about 45 per cent of all licenced water use, according to the Department of Water and Environmental Regulation’s most recent annual report.
BHP’s dewatering exercise will be integral in expanding operations at its key Mining Area C iron ore hub. The dewatering will require construction of two pipelines to pump out groundwater and dry out the pit so it can be mined.
“This application has no impact on pastoral, town or residential water users,” a BHP spokesman told The West Australian. “It relates to a continuation of a long-standing industry process, where water is removed from mine pits as mining extends below the water table.”
He said BHP was committed to responsible water use. Mining Area C has so far returned 86 per cent of what BHP considers “surplus water” by injecting it back to the regional aquifers or into creeks.
It’s estimated about 30 per cent of the water is used for mining operations, including to spray on iron ore stockpiles to minimise dust and ore loss, as well as in its ore processing, and for mining camps.
The financials of building a desalination plant, which would turn saltwater into potable water, would be logistically and financially challenging given Mining Area C is hundreds of kilometres away from the ocean.
But BHP’s bid to alter its water licence comes amid heightened scrutiny on how water use is monitored in WA.
The recent report from the Auditor General’s Department was scathing of the DWER’s policing of water usage, revealing the concerning finding that 12,000 water licences which in total allowed the extraction 4 trillion litres of water each year, were not being monitored effectively.
While there is no suggestion BHP hasn’t complied with its water licences, the lack of oversight raises concerns as to how well the State’s water supplies are being monitored and researched.
Perth-based geohydrologist Dr Ryan Vogwill is concerned that the confluence of less rainfall in the Pilbara over the past 15 years, combined with the increased draw from miners, is making it harder for aquifers to recharge.
“Essentially in many cases we have a legacy of projects and allocations approved under the assumption of a wetter climate than has occurred,” he told The West Australian.
He believes there is not enough funding being allocated to DWER, which is already understaffed per the Auditor General’s recent findings, to figure out exactly how the draw and subsequent pumping back into the ground are impacting the Pilbara’s ecosystems.
“There is urgent need for DWER to undertake a detailed review of impacts holistically across the entire Pilbara, including increasing climate and water monitoring to help better understand these complicated issues,” he said.
“We also need to better understand how and where the environment in the Pilbara is groundwater dependant, including detailed environmental water requirements (what the environment needs to stay healthy) not only near mines but across the Pilbara generally.”
A spokesperson for DWER said a recent lack of cyclonic rainfall was making it harder for the underground aquifers that supply coastal towns and industry to recharge.
As a result, they said the division had brought in new targets to increase the amount of field audits and compliance reviews “in a targeted approach to preserve the future of Western Australia’s water resources”.
“Our increased focus on water compliance is consistent with the recent findings of the Auditor General, which highlighted the need for greater oversight and protection of our water resources.”
An extra $4.2 million was allocated to DWER in the State’s recent budget for water planning, with just over half of that to cover the costs of five new staff for two years and $1.7 million going towards groundwater monitoring infrastructure.
