Prepare a pre inspection information pack for your reservoir

Keep records for the lifetime of the reservoir

You must provide the information and facilities to any engineer appointed to your reservoir so they can do their job properly. You could commit an offence if you don’t provide these.

You should keep all the information relating to your reservoir so that it is secure but accessible by those who need it. You should keep these records for the whole operating life of the reservoir. They may be requested by us or an engineer at any time.

Paper drawings, photographs and other physical records deteriorate over time, and you should arrange for high quality digital copies to be made. Check all copies to make sure information is not lost or distorted in the process. Keep the original documents safe.

If there is an incident at your reservoir, you may be asked to provide information at very short notice. Your flood plan should include instructions on how to access the information.

Pre-inspection information pack

Before an inspection, your Inspecting Engineer will request information from you. The best way to do this is by maintaining an information pack. Keeping this up to date and reviewing it regularly is better than one big effort before an inspection.

Your Inspecting Engineer may want all or just some of the information you hold but you should be able to provide a list of what is available. If you have a lot of documents, you should keep a contents page or use an indexing system.

Read our guidance on how to arrange a reservoir inspection.

The contents of an information pack

We suggest you organise the information under the following headings and give the most recent information first. Some of the documents listed may not be appropriate for your reservoir. If you do not have the information, it is helpful to include the heading and mark the entry as “Does not exist”, or similar. You may be asked to acquire the information.

Design and Construction

You should provide documents which illustrate how the reservoir was built, including:

  • Construction drawings and design documents for the original structure
  • Drawings and details produced after initial construction which illustrate the current as-built structures.
  • Hydraulic, structural, geotechnical and other design calculations.
  • If required by the Construction (Design and Management) Regulations 2015, include the health and safety files in this section.

Risk assessment

You should provide a copy of your latest risk assessment for the safety of the reservoir.

Risk assessment for reservoir safety (known as RARS for short) is often done using the UK guidance.

Read Risk assessments for reservoirs on GOV.UK

You should consult with the Inspecting Engineer as to which level of assessment is most appropriate. The RARS guide uses a three tier approach:

Tier 1 uses a simpler qualitative assessment method

Tiers 2 and 3 use increasingly more detailed quantitative methods and are aimed at:

  • Reservoir undertakers, owners and operators
  • Construction, Inspecting and Supervising Engineers

Statutory documents

You must keep all statutory documents provided by qualified civil engineers, including:

  • Certificate of Efficient Execution of Works including any annexes
  • Preliminary, Interim and Final Certificates of Construction including any annexes
  • All section 10 inspection reports and certificates, including decisions and alterations given by a referee engineer
  • All section 12 statements by Supervising Engineers and any section 12(6) directions for visual inspection given by Supervising Engineers
  • Incident and near miss reports

Prescribed Form of Record

Your Prescribed Form of Record should record the information you collect as part of your normal monitoring, equipment testing, damage or unusual events. If the items recorded in your Prescribed Form of Record have any supporting documents, you should keep these securely but readily available.

You should provide any routine analysis and interpretation of:

  • Trends in the data and odd results
  • Any gaps in the data
  • Known monitoring system failures.

These maybe provided in the statements provided by your Supervising Engineer.

Flood plan

Make your flood plan available to the Inspecting Engineer. You may also be asked for any recommendations given by the Supervising Engineer to revise or test your flood plan.

Survey and investigation data

You should be able to provide survey reports, data and other information about the reservoir over its whole operating life. These commonly include:

  • Topographic and bathymetric surveys
  • CCTV surveys
  • Visual inspection, drone and aerial photography surveys
  • Structural and condition surveys
  • Tree, wildlife, environmental and ecological surveys

More complex issues may generate:

  • Geological and geophysical surveys
  • Utility, services and drainage surveys
  • Archaeological surveys
  • Mine working enquiries or surveys
  • Unexploded ordnance surveys

Previous studies

Provide reports relating to the dam, its structures and the surrounding area, such as:

  • Spillway capacity assessments
  • Draw-down capacity assessments and tests
  • Condition assessments of structures, pipework, valves and gates
  • Flood risk assessments and dam breach flood maps
  • Geotechnical investigations
  • Seepage investigations
  • Stability assessments
  • Hydraulic modelling
  • Laboratory materials testing

Photographs and video

Collect together photographs and video which provide an historic timeline of changes. An effective photographic record should provide both a general view of the reservoir over time and record specific locations.

The photographic record should:

  • Show the same angle over time during both normal and unusual conditions
  • Include areas of damage, deterioration or other matters of concern such as cracking, slumping, wet spots and vegetation problems
  • Show the upstream face of the dam at different water elevations
  • Include images of sub-surface investigations, such as trial pits and their locations
  • Show structures under unusual conditions, for example, during very cold or windy weather, flood events or during a reservoir drain-down.

You should also use photos and video to record areas where access is not normally possible during a routine inspection. For example, take photos when the water level is low which shows structures normally underwater, or areas where access is dangerous without special equipment.

Include historic photographs which may be available on the internet, at your local library or at a records office.

You may also find useful information by looking at old maps over different periods of time.

You can compare maps on the National Library of Scotland's Side by side georeferenced maps viewer

The Royal Commission on the Ancient and Historical Monuments of Wales also holds useful information on reservoirs in several searchable databases.

You can search reservoir records on the RCAHMW website

Cadw is the Welsh Government's historic environment service working to protect the historic environment for Wales.

Search for records on the Cadw website.

Historical and superseded documents

You should keep an archive of all documents that have been superseded. Make sure they are marked “superseded” or similar. For example, design drawings which have been superseded by drawings of improvement works, and flood studies which have been updated to reflect current methodology.

Incident reports

Include all post-incident and near miss investigation reports for the entire operating life of the reservoir, including how any recommendations or lessons learnt have been applied.

Other important or requested information

Include any other information that is available that may be useful. For example, useful observations since the last inspection from:

  • Observations and complaints from local people
  • Future intentions, for example installation of hydro-electric power

Identify missing information

You should seek to identify any gaps in the information you have. Gaps in information can lead to assumptions which may be incorrect and over time they may be wrongly accepted.

Your engineers should use their judgement to advise you what action to take to obtain or replace missing information.

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