Reservoir safety supervision for Bristol Water’s dam portfolio

In the UK, dam safety is governed by the Reservoirs Act 1975. This requires reservoir owners to appoint an independent Supervising Engineer to oversee the condition and performance of each asset, and to provide ongoing advice on safety and compliance.

Bristol Water operates 15 large raised reservoirs across the west of England. These assets are essential for water supply but also present potential risks if not carefully managed. Failure could have serious consequences for people, property and the environment downstream.

Alongside their operational role, these reservoirs are important community and environmental assets. Sites such as Chew Valley Lake and Blagdon Lake support wildlife, recreation and wellbeing.

Bristol Water needs confidence that its reservoirs are operating safely, meeting legal requirements and continuing to deliver long-term value for people and the environment.

HR Wallingford has delivered Supervising Engineer services for Bristol Water since 2012, providing continuity and trusted, independent advice.

We carry out six-monthly inspections of each reservoir and its associated structures. We do this to identify early signs of deterioration, assess current condition and ensure that each asset continues to perform as expected.

Alongside these inspections, we produce a comprehensive annual report for every reservoir. This brings together monitoring data, inspection findings and long-term trends. We do this to provide a clear picture of how each dam is behaving over time, helping Bristol Water make informed decisions about maintenance and investment.

We provide practical, risk-based recommendations on monitoring, maintenance and any required interventions. This ensures that actions are prioritised effectively and aligned with both safety requirements and operational needs.

Our approach focuses on long-term understanding. By combining regular inspection with data-led insight, we help identify potential issues early and reduce the likelihood of more significant problems developing.

This work helps Bristol Water manage its reservoirs safely, responsibly and in line with legal requirements. Regular, independent oversight reduces the risk of dam failure, helping to protect many thousands of people living downstream and providing reassurance to communities.

Clear, practical advice enables Bristol Water to meet the requirements of the Reservoirs Act 1975 with confidence, reducing the risk of enforcement action while supporting more efficient planning of maintenance and investment.

At the same time, safe and well-managed reservoirs continue to support important freshwater environments. Sites such as Chew Valley Lake and Blagdon Lake provide valuable habitats for wildlife while also offering spaces for recreation, including fishing and sailing, contributing to wellbeing and quality of life.

Together, these outcomes ensure that essential infrastructure continues to deliver lasting value for people, the environment and the wider region.