New and updated reservoir flood mapping

The public release of new and updated nation-wide 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.

Following on from 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 supported the formulation and publication of a new reservoir flood modelling and mapping specification, collated and updated influential reservoir data and produced improved and updated reservoir flood mapping across England.

New and updated reservoir flood mapping - JBA Consulting

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 inform and support the reservoir management of associated flood risks and emergency planning. During the project it was possible to make use of the available improved modelling and mapping information to provide real life tactical support for the incident at Toddbrook Reservoir in August 2019. This clearly evidenced the value of the improved modelling and mapping data to actually address risks posed by large-raised reservoirs to people, businesses, property and infrastructure.

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.

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 as have been observed over recent years from events experienced around the world.

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 lifetime.

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 was closely inspected by a team of experienced reservoir panel engineers whose knowledge of reservoir systems added the necessary value and confidence in project outputs.

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.

Want to know more?

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

You may also be interested in our case-study about reservoir surveys.

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