REMOVING willow trees from river banks could return hundreds of megalitres of water to struggling river systems, research by the CSIRO has found.

Tanya Doody, the leader of the study and an eco-hydrologist, said about 5½ megalitres of water could be saved for every two to three kilometres of willow canopy removed from streams or river beds.

Common sight ... but willows are an introduced species. Credit:iStock

''That's the same as 550 millimetres of rainfall,'' she said.

Willows, an introduced species, are common throughout the country, especially along creeks and rivers in south-eastern Australia.