Australia's drinking water reserves are under threat as increasingly dry weather reduces the rate at which groundwater aquifers replenish.
Perth relies on groundwater to supply 40 per cent of its drinking water as well as water for agriculture, private gardens and open spaces, and its water requirements will only continue to grow as its population increases.
But the Gnangara aquifer system that sits under the city is refilling 70 per cent slower than it did half a century ago, a team of researchers has discovered, sparking grave concerns for its sustainability.
The study, published in the Journal of Hydrology earlier in March, found winters have become shorter since the 1960s, with fewer and weaker storms, dramatically reducing the system's refill rate.
"Our findings suggest groundwater aquifers in climates like Perth's are particularly vulnerable to climate change, and may see larger recharge declines, as soil needs to be saturated with rain before water trickles down to aquifer level," said University of Western Australia researcher Dr Simone Gelsinari, who led the study.
Groundwater recharging is highly sensitive to changing weather patterns.
Previous studies have found changes in rainfall seasonality in southeast Australia could reduce recharge, even if total annual rainfall is constant.
Joel Hall, study co-author and principal environmental modeller at WA's Department of Water and Environmental Regulation, said understanding how groundwater replenished was vital to managing competing demands from water users and the environment.
"Partnerships between water managers and researchers are more important than ever to help us meet this challenge in our drying climate," he said.
