Reservoir Safety

The Reservoirs Act of 1930 was passed following two dam failures in Scotland and Wales in 1925.  It has since been superseded by the Reservoirs Act 1975 which remains the primary instrument for reservoir safety in Great Britain.  The 1975 Act provides the legal framework to ensure the safety of British reservoirs that hold at least 25,000 cubic metres of water impounded above natural ground level. 

Approximately 2,500 reservoirs are covered by the Act with some 88% being formed by embankment dams and the remainder comprising concrete or masonry dams or service reservoirs.  

In 2004, in England and Wales, responsibility for enforcement of the Act was passed to the Environment Agency. Responsibility for enforcement of Welsh reservoirs has since been passed to Natural Resources Wales, at its formation in April 2013. Responsibility remains with the Scottish Executive and councils for Scotland. 

The Reservoir Safety cross-cutting research area identifies the research needed to design, construct, manage, monitor and operate reservoirs safely. Research priorities and gaps are set out in our Reservoir Safety Research Strategy.

Please note that the strategy is currently being refreshed and a new version will be published in 2016.

Key research areas include:
Appurtenant structures
Many UK reservoirs were constructed over a hundred years ago. The ancillary equipment was designed and built or manufactured at the time of construction. Some is still fit for purpose but others can be significantly improved through modern technology.

Climate Change
Assumptions are made when designing dams of how the environment will impact on the way that they work. As our understanding of the climate changes it is important to understand how these changes will affect existing dams and how they can be adapted in response to climate change.

Concrete dams
Only 12% of UK stock of Dams are made in concrete. However these dams tend to be the largest and therefore more likely to have significant consequences in the event of failure. It is because of the age of current dams and because dams are long term structures, they exceed the boundaries of our knowledge of how concrete performs over long periods.

Dambreak analysis
When a dam fails it will often be catastrophic. The different behaviours of the dam through the minutes and hours of failure will significantly affect the consequences of the failure. A better understanding of the methods of failure will help us to plan emergency response.

Hydrology and hydraulics
Dams have to cope safely with extremes of weather and therefore designers work at the edge of confidence levels for hydrology and hydraulics. A better understanding of the challenges that those extremes represent helps us to design better safer dams.

Risk and emergency planning
In designing dams we do everything we can to minimise the risk of damage to property and loss of life. Part of this process is putting in place emergency plans. These need to be brought up to date in light of experience, and developing methods and technologies.