Last week, the Leith river, which runs directly through the university campus, flooded to the extent where its banks were at risk of bursting, resulting in the evacuation of 36 nearby properties. While the flood left plenty of visible debris in its wake, such as picnic tables and shopping trollies, there will also be an environmental aspect to the aftermath of the flooding event. We spoke to Professor Chris Hepburn (Department of Marine Science, University of Otago) to learn more about the impact of such both natural and human pollution on waterways.