Time Out says
Hot day? Head to our closest National Park and enjoy the soothing wilderness of leafy Warrandyte. As far as Yarra River swimming goes, you won't do better than Pound Bend. In 1870, gold miners dug 145 metres of rock through a hill to divert the Yarra through a tunnel to dredge for gold. Nowadays, the mouth of the tunnel opens out into a calm, deep river oasis that the locals have been keeping secret. Take a quick dip, chill out by the banks or bring your blow-up tyre and just float.