Creating an on-site Reservoir Flood Plan

On 21st April 2021, a Ministerial Direction was issued that stated a ‘Flood Plan’ must be produced for every high-risk reservoir in England.

Certified flood plans were recommended following the independent review of the Toddbrook Reservoir Spillway Failure in Summer 2019. Now mandatory in England, flood plans must be produced for all reservoirs registered under the Reservoirs Act 1975 by 21 April 2022 (with a capacity greater than 25,000m³). All flood plans must also be certified by a qualified reservoir engineer, and to ensure high-risk reservoirs are properly maintained these plans must be recertified every five years.

Creating an on-site Reservoir Flood Plan - JBA ConsultingKey features of a flood plan

  1. Reservoir and dam features
  2. Triggers and actions
  3. Emergency contacts and communication channels
  4. Breach map
  5. Roles and responsibilities
  6. Maintenance and testing requirements
  7. Safe access routes and marshalling points
  8. Drawdown and pumping requirements
  9. Health and safety security
  10. Reservoir construction drawings and photographs

To date we have written more than 60 onsite flood plans for reservoirs nationwide, on behalf of various clients including councils, the Environment Agency, The National Trust, and private owners. Although the requirement for flood plans is not mandatory in Scotland, Wales and Northern Ireland, we have also developed flood plans for clients including Natural Resources Wales, Denbighshire County Council and Northern Ireland’s Department for Infrastructure.

Flood plans should be treated as a ‘living’ document and updated on a regular basis. It is advised that the plans are updated as follows:

  • If any details or information in the plan changes (e.g. modifications to the dam, change in contact details, areas at risk of flooding downstream change)
  • At least every year
  • Before the appointed engineer issues a new section 12AA (3) certificate
  • Following every exercise of the on-site plan
  • Following an emergency reservoir dam incident
  • As part of a statutory inspection (conducted by an Inspecting Engineer under the Reservoir Act)
  • Every 5 years (to be renewed and recertified)

For a plan to be effective, it must be tested and exercised. Additionally, responders and key personnel should be trained on how and when to use the plan. As part of the Ministerial Direction, it is mandatory to test a flood plan at least once every 10 years. Every test should include a formal debriefing and lessons learned report, with changes made to the flood plan as appropriate.

Want to know more?

For more information about our knowledge and experience in this area visit our Reservoir Management page, or for more details about creating a Flood Risk Plan please contact Jeremy Benn.

More information about reservoir emergencies and on-site plans can be found here.



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