JBA contribute to innovative new reservoir flood mapping products

The public release of new and updated nationwide Reservoir Flood Maps showcases the efficiencies, innovation, and capacity that we have delivered to the Environment Agency in meeting the obligations associated with managing reservoir flood risk.

Written by Iain Craigen | Chartered Senior Analyst

The Pitt Review

Following the Pitt Review and its recommendations in 2008, we were involved in the first round of National Reservoir Inundation Modelling in 2010. Since then we have:

  1. supported the formulation and publication of a new reservoir flood modelling and mapping specification
  2. collated and updated influential reservoir data
  3. produced improved and updated reservoir flood mapping across England

The enhanced outputs from the latest Reservoir Flood Mapping provide the best available information to all stakeholders associated with large-raised reservoirs. The improved mapping and modelling outputs also inform and support the reservoir management of associated flood risks and emergency planning.

The project team

To deliver the £2.5M, three-year consultancy modelling and mapping commission, we led a multi-consultancy team supported by Mott MacDonald and BMT to provide an experienced project team of reservoir flood modellers, panel engineers and hydraulic modelling software developers. Adopting integrated working practices, the project team performed an initial pilot test of the methods required to meet the updated specification and subsequently established efficient working practices to roll out the updated reservoir flood mapping outputs.

Project deliverables

The mapping outputs now include the flood risks associated with reservoirs both when river levels are normal (dry day), as well as for a breach that happens when there is also flooding in rivers (wet day). The reservoir flood modelling and mapping predictions are based on potential reservoir flood scenarios and risks that have been experienced and observed at incidents around the world over recent years.

Whilst the project’s coverage was national scale across England, each reservoir assessed comprised an individual and independent hydraulic model to represent the multiple potential flood directions, local flow pathways and interactions with structures and the river network downstream. To work cost-effectively at such detail nationally relied on our specialist skills in software development and deployment of modelling teams to streamline and maximise efficiency in model development, analysis, quality assurance and mapping. All reservoir data and flood mapping were closely inspected by a team of experienced reservoir panel engineers whose knowledge of reservoir systems added the necessary value and confidence in project outputs.

How will the new reservoir flood maps be used?

The improved modelling and mapping products will be invaluable in addressing new requirements on reservoir owners and undertakers to develop off-site and on-site emergency plans and continues the lifecycle of reservoir flood risk management. Something which we continue to support through our hydrology, modelling and reservoir panel engineer services.

Hydraulic modelling and innovation

Over 1,850 reservoirs in England required efficient, new, and updated modelling and mapping at high resolution and accuracy. The project team utilised the latest TUFLOW HPC hydraulic modelling software and the most up-to-date LiDAR data available. This was paired with a technology platform that drew on our continued investment in powerful IT computational processing and digital communications technology to enable over 55,000 simulations to be carried out 24/7 throughout the project’s lifetime.

Hydraulic modelling and innovation
Hydraulic modelling and innovation
Hydraulic modelling and innovation
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Want to know more?

For more information about the new and updated reservoir flood mapping, please contact Iain Craigen.


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