Dams and reservoirs are critical infrastructure; they provide a water supply, a source of recreation, and mitigate flood risk. In the UK, more than 2000 reservoirs hold over 25,000 m3 of water each. Around 2.6 million people are at risk from reservoirs and dams failing and flooding so maintaining these structures is essential to protect downstream communities. But issues like climate change, ageing infrastructure and the need for updated regulations are forcing us to rethink how we look after our reservoirs.
Reservoirs in crisis
As recently as 2019, the spillway at Toddbrook Reservoir in Derbyshire was badly damaged after days of heavy rainfall. 1500 people were evacuated from local towns and villages in case the dam collapsed. Poor design and poor maintenance, exacerbated by the torrential downpour, were considered the key contributors to the incident. Facing complete reconstruction, the reservoir will reopen this summer, six years on.
In April 2025, the Environment Agency (EA) and the Department for Environment, Food and Rural Affairs (Defra) initiated the Reservoir Safety Reform Programme. The programme aims to modernise reservoir safety management and protect communities in England and Wales. It was created in response to
- The Toddbrook incident (2019) and the Independent Reservoir Safety Review
- Climate change, with its increasing pressures on reservoir infrastructure and demand for reservoirs and water resources
- The need to update the Reservoirs Act 1975 to a more proportionate and flexible regime. This aligns with safety management practices in other sectors and countries
- Concerns about the limited number of reservoir engineers and the increasing demand for specialist engineers.
Our role in the future of infrastructure
These drivers speak closely to us in the Department. Our teaching and research are influenced by the need to respond to the challenges around us and keep sustainability at its core. We do this by training responsible engineers who can fill the specialist roles needed in the future. And our researchers are finding ways to better understand and mitigate risk, as well as developing innovative solutions to respond to it.
Our civil engineering undergraduates study the design of hydraulic infrastructure. This includes aspects of risk-based design, resilience and sustainability. They also practise these skills in projects where they have designed hydropower schemes, tidal lagunes, and offshore wind farms. Our students can also dive deeper into risk and uncertainty in civil engineering through topics such as decision-making, black swan events, and uncertainty assessment.
Research shaping policy and procedure
Our teaching and research are closely interlinked, so our students directly benefit from the latest research findings and innovations. Dr Mohammad Heidarzadeh has developed a cascading risk model to better understand the sequence of events causing the Toddbrook incident.
Dr Thomas Kjeldsen is a member of the Defra/ICE Reservoir Safety Research Advisory Group and leads the hydrology and hydraulics research theme. He is developing new and improved methods to predict the magnitude and frequency of extreme floods, including the potential impacts of climate change. Teaming up with Wallingford Hydro Solutions (WHS) and the UK Centre for Ecology & Hydrology, they have updated the procedures for estimating the probable maximum flood (PMF) using modern hydrological methods.
'The hydrological methods underpinning reservoir safety assessments in the UK are outdated, based on models and data that are more than 50 years old and with no consideration of potential climate change impacts. Updating these methods is urgently needed to ensure the safety of our critical infrastructure.' - Dr Thomas Kjeldsen
Both Thomas and Mohammad have recently authored books relating to dam safety and resilience. 'Risk and Uncertainty for Civil Engineering' and 'A Practical Approach to Advanced Mathematical Modelling in Civil Engineering' will further support our undergraduate students’ learning experience.