The bark is OK but the leaves do not look right. Unfortunately the key in VicFlora uses hairiness and colour of the backs of the leaves as characters for IDing.
Mike the back of the leaves of Populus alba are white, while those of Eastern Cottonwood are pale green - bit hard to tell from the photos - but I think Eastern Cottonwood
Thanks Betty & Michael. I couldn't get any closer because of the river. Will confirm Michael's suggestion, and hopefully get some better pics later if the river goes down.