It’s a cold, golden morning and you’re out for a wild swim. Mist rises from the river, and the air smells of frost and moss. You already know the dive will freeze your bones, and you’re shaking with anticipation of that first smack of ice and the moment of clarity it will bring. 20 years ago this was a putrid stream, a victim of the Victorian sewage system. When rain swelled the old pipes, they burst with foulness, polluting the stream and driving away wildlife. Advocates, many of whom belonged to the wild swimming community, had worked tirelessly, fighting the private companies who control water and sewage services, and getting the government to prioritize the modernisation of sewage systems. It took many years, but it worked. Rubbish had been more difficult, with much of what landed on streets being washed into gutters and finally to waterways. This, too, changed with the passionate advocacy of others. As single use plastics disappeared, waterways cleared up, giving space for amphibians, fish, and birds to return. Now, as you stand toes over the grassy bank edge, dark fish dart and flash beneath the water, and water boatman skate across the surface on dimpled tracks. A great heron stands in the distance, neck an S coil. You fill your lungs with bright air and take the plunge.