Dams disrupt a range of environmental conditions and processes in rivers. A crucial, and understudied one, is how dams change temperature dynamics in rivers. Large dams typically stratify from spring to autumn, with warm lighter water on top and cold denser water at the bottom. Most dams release water from the bottom layer (hypolimnion), where the temperatures are generally 12-13oC. The release of this water into downstream rivers is called coldwater pollution. The changes to temperature regimes can have significant negative impacts of the animals and functioning of river ecosystems.

We are working to understand the dynamics of coldwater pollution and its impacts on ecosystems (Gray et al. 2019, Michie et al. 2020, Michie et al 2025). Working with our colleagues in NSW Fisheries we are implementing solutions and will be documenting how ecosystems change in response remediation action of the coming years.