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Know when to appoint an engineer

The main principles of the Reservoirs Act 1975 is to ensure large raised reservoirs are built, altered, brought into use, supervised, maintained, abandoned and discontinued under the guidance of qualified civil engineers

These are specialized civil engineers with detailed information about working on dams and reservoirs. These engineers are also called panel engineers because they must be assigned to one of four specialist panels for different types of reservoirs and activities. The lists of engineers panel available from us when requested.

Construction, alteration and re-use of reservoirsundefined / undefined

Before you build a large raised reservoir, or alter it to change its capacity, you must appoint a qualified civil engineer known as a construction engineer. They must belong to one of the approved panels, depending on the type of reservoir to be constructed or altered. You should appoint them at an early stage of the design so they may advise you properly.

A Construction Engineer must also be appointed before you bring an abandoned reservoir back into use, so that they may report on any safety measures to be taken prior to refilling.

A Construction Engineer can be chosen from the All Reservoirs Panel for any reservoir, but there are additional panels for non-impounding and service reservoirs.

You must tell us about the appointment and provide some specific engineering information more than 28 days before the work begins. You can request a notification form from us.

Abandonment and discontinuance

Where you no longer have a use for your reservoir, or that use temporarily suspended you may consider abandonment or discontinuation to reduce or remove the obligations placed on you as the undertaker. Under no circumstances must you consider your reservoir to be abandoned or discontinued without the involvement and certification of a qualified civil engineer. Until you have received a copy of the engineer’s certificate you must fulfil all your obligations under the Reservoirs Act 1975. This applies to all reservoirs, not just those which are high-risk reservoirs.

Abandonment and discontinuance can be designed and supervised by an engineer from the All Reservoirs Panel for any reservoir, but there are additional panels for non-impounding and service reservoirs.

Abandonment is the process of modifying your reservoir so that its dam or embankment remains intact but so that it is incapable of filling naturally or accidentally, or to an extent where it does not constitute a risk. To seek formal abandonment of your reservoir you must appoint a qualified civil engineer. The engineer will provide you with a report and if necessary any measure that ought to be taken in the interests of safety.

Abandoned high-risk reservoirs must still have a Supervising Engineer appointed and be inspected periodically in accordance with Section 10 of the Reservoir Act.

Discontinuance requires sufficient work to confirm to the satisfaction of the engineer that your reservoir is no longer capable of holding 10,000 cubic metres of water, in effect:

  1. The dam or embankment is wholly or partially removed and no water is stored above natural ground level, or
  2. The reservoir is retained, but the capacity is reduced to below the regulatory threshold of 10,000 cubic metres

In both cases the alteration works must be carried out under the guidance of a qualified civil engineer. The engineer may provide you interim certificates determining safe water levels during the discontinuance process. A copy of all certificates should be sent to us.

Discontinuance may require other consents from us or from other authorities such as your Local Planning Authority.

When all discontinuance works have been completed the engineer will provide a certificate confirming that the works have been efficiently executed. When we receive this certificate, we will remove the reservoir from the register of large raised reservoirs.

High Risk Reservoirs – additional requirements

Prescribed Form of Record (Blue Book)

You must keep and maintain a Prescribed Form of Record (PFR) for all high risk reservoirs; you may hear others refer to the ‘Blue Book’ as this was the traditional colour of the paper publication. A well-kept PFR will:

  • Provide you and engineers important information about the reservoir that will be valuable in the event of any problem that may affect reservoir safety
  • Act as a diary of the life of the reservoir in recording its behaviour, problems and maintenance. Small recorded changes over time may flag more serious defects

You must keep the Prescribed Form of Record up to date with the information you collect from readings, measurements, investigations, engineer appointments, etc.

Supervising engineerundefined / undefined

A Supervising Engineers provide information about the behaviour of your reservoir and are available at all times to provide advice

If you own or operate a high-risk reservoir you must have a Supervising Engineer appointed at all times. The engineer will visit periodically and advise you on the behaviour of the reservoir. They will provide you annually with a written statement of their findings; this is often known as a Section 12 or Annual Statement.

The term “at all times” means the engineer is available to provide you with advice, even if this is by telephone. It is normal practice for them to inform you of temporary cover during periods of unavailability, eg if they are on holiday.

Supervising Engineers can be appointed to any of the four panels.

Periodic inspections

All high-risk reservoirs must be inspected periodically at the following times:

  • Within two years of receiving a final certificate for a new or altered reservoir
  • As soon as practicable following any work that might affect the safety of the reservoir, where the work has not been designed and supervised by a qualified civil engineer
  • Before the date specified in your latest inspection report
  • When your Supervising Engineering notifies you to do so
  • Not more than 10 years since the last inspection

For newly registered reservoirs which were not previously in an inspection regime, you must arrange for an inspection within one year of receiving our notice of final designation confirming your reservoir as high-risk.

Inspecting Engineers can be selected from the All Reservoirs Panel for any reservoir, but there are additional panels for non-impounding and service reservoirs.

The Inspecting Engineer will provide you with a report of their findings and recommendations. You should read the report carefully and seek clarification on anything which you do not understand. 

Measures in the Interests of Safety

An inspection report may contain Recommendations as to Measures to be taken in the Interests of Safety (MIOS). This is the legally correct term for work that you must do to ensure your reservoir stays safe. You should make sure you understand what the engineer is recommending. If you cannot agree with the recommendations made by your engineer a referee may be used. 

When an engineer is satisfied the works are complete, they will send you a certificate confirming this. They should also send a copy of the certificate to us within 28 days – you should check to make sure they have done this. In summary, MIOS are:

  • Important for the safety of the reservoir and you should attend to them promptly
  • Legal requirements which you must implement within the timescale given
  • Enforceable by us

Measures in the Interests of Maintenance

Measures in the Interests of Maintenance (MIOM) may be recommended by your Inspecting Engineer. We recommend that records of this work is kept by you and described in your Prescribed Form of Record. In summary, MIOM are:

  • Routine maintenance activities to prevent deterioration which would affect the safety of your reservoir
  • Obligatory activities, where failure to complete them may be considered an offence

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