Sydney's drinking water could be polluted by bushfire ash in Warragamba Dam catchment, expert says

Large deposits of sediment and ash in reservoir which supplies 80% of the city's drinking water creates 'serious situation'

Sydney's drinking water supply is at risk of the same "worst-case scenario" facing some New South Wales regional communities, where large amounts of bushfire ash has been swept into dams by heavy rainfall, a water expert has warned.

Stuart Khan, a water quality security expert and environmental engineer from the University of NSW, said recent bushfires had left large deposits of ash in the Warragamba Dam catchment, which supplies 80% of the city's drinking water.