In England, a large raised reservoir is defined in the Reservoirs Act 1975 (as amended), as a body of water that is capable of storing 25,000 cubic metres or more of water above natural ground level.
If such a reservoir is designated as ‘high-risk’ by the Environment Agency (the relevant regulatory authority in England), it means that an uncontrolled release of water resulting from a failure of the structure could pose a danger to human life.
To ensure compliance, a large raised reservoir is required to meet all the requirements of the Act, while others still have certain requirements to meet.
The owner, operator or user of a reservoir is termed the undertaker. The undertaker is responsible for making sure they meet the requirements of the Act. These include ensuring they have the appropriate panel engineers appointed and that they carry out any essential safety work identified by their engineer.
Panel engineers are appointed by the undertaker to:
- Oversee the construction of a reservoir
- Supervise a reservoir
- Carry out inspections
- Provide advice on and oversee maintenance and repairs
There are different types of panel engineer depending on what stage of life your reservoir is at.
- Construction engineer
- A construction engineer is required when a reservoir is being built so they can design and oversee the works. They are also required when making any changes to the water level of an existing reservoir to increase or decrease its capacity.
- Inspecting engineer
- An inspecting engineer is necessary to complete a full safety inspection of the reservoir, which usually happens at least once every 10 years, but can be sooner if recommended by the last inspecting engineer or called for by the supervising engineer.
- Supervising engineer
- A high-risk reservoir must have a supervising engineer appointed at all times. They will visit at least once a year and provide a written statement on the safety of the reservoir. They also create and certify flood plans, which are required for both high-risk and not high-risk reservoirs.
Please see the Reservoirs team website, where you will find advice on how to appoint an engineer for your reservoir, as well as further information on this topic.