2024 – Dam Decommissioning: Challenges and Key Considerations

Josh Kline, Nicholas Thomas-Kinsella

Many dams have multiple uses and benefits, though over time, these may become redundant or external pressures, whether financial, environmental, regulatory or life safety based, may test the need to continue to maintain and operate an existing dam. Dam decommissioning rates are growing in parts of the world, such as the US and parts of Europe, but what is the real cost of decommissioning?

The decision to maintain or decommission a dam may have numerous benefits, costs and risks that might not be initially well understood by dam owners. Furthermore, growing emphasis on the use of quantitative risk assessment is requiring dam owners to apply the As Low As Reasonably Practicable (ALARP) principle for evaluating risk reduction measures. In line with the ALARP principle, although it may not initially be considered favourable, decommissioning is a risk reduction measure that should be considered.

This paper presents the current state of practice for dam decommissioning, with a particular focus on decommissioning as a form of risk reduction, and with consideration of the whole-of-life costs associated with the ownership of an unused dam compared with the social, regulatory, environmental, economic, cultural and technical challenges associated with decommissioning.