Curtains and booms to trap silt and ash from bush fires have been installed at the Warragamba Dam, Sydney’s main source of drinking water, to prevent water contamination, according to the reservoir’s website.

Severe storms are expected to bring some relief in the coming days from huge bush fires scorching Australia but the heavy downpours could also carry the risk of landslides and water pollution, officials said on Wednesday.

Heavy rainfall can pollute fresh water supplies as debris is swept into reservoirs. They can also cause flash flooding, leaving burnt-out areas of bush land particularly vulnerable to landslips and tree falling.

Warragamba Dam is located 65km west of Sydney, catching water flowing from the mountains.

It is currently at 44.8% capacity, down from almost being full less than three years ago, as a prolonged drought ravage the continent’s east.

Australia is battling its worst bush fire season on record, with fires burning since September killing 29 people, destroying more than 2 500 homes and razing bush land across an area the size of Bulgaria.