Karratha, a major city in Western Australia's North West, is experiencing critical water supply issues as the region faces an ongoing extreme heatwave. The primary water source, Harding Dam, has reached its lowest level since 1987, prompting concerns for the city's long-term water security.
Water Supply Challenges
The Harding Dam, located near Roebourne and serving as the main water source for the Pilbara, recorded 10.69 gigalitres (16.8 percent full) in January, marking its lowest capacity in nearly four decades. Water becomes unsuitable for supply when the dam drops below 18 percent capacity due to quality concerns.
Currently, water is being drawn from the Millstream aquifer, a culturally significant site for the Yindjibarndi people. Both the dam and the aquifer rely on rainfall, leading to increased pressure on resources during dry periods. Water Corporation North West regional manager Sharon Broad noted an 80 percent reduction in annual inflows over the past 30 years due to hotter conditions and less rain. Despite the record low, water restrictions are not currently planned.
Extreme Heatwave Conditions
Simultaneously, the Pilbara and Gascoyne regions are under an extreme heatwave warning, with temperatures forecasted to approach 50 degrees Celsius. Onslow previously recorded Australia's equal highest maximum temperature at 50.7C in 2022. The Bureau of Meteorology (BOM) indicates that further temperature records could be set, though some may go unverified due to limited weather station coverage. A tropical low, 16U, is forming north-west of the Kimberley and has a chance of developing into a tropical cyclone later in the week.
Impact and Future Solutions
The shift to Millstream aquifer water has presented challenges for local businesses, such as Karratha nurseries, where the higher calcium content affects plant health.
In response to the escalating situation, the Western Australian government and Rio Tinto are collaborating on plans for a new desalination plant at the existing Dampier operation. This initiative aims to provide a less climate-reliant water solution for the future. Adjunct professor Bill Grace of the University of Western Australia commented that desalination plans should have been considered earlier, citing predictable outcomes based on historical climate records and increasing demand. He attributes the current water crisis to a combination of regional growth, significant water demands, high temperatures, and insufficient rainfall.