Last week saw the release of the UK government’s National Flood Resilience Review. This blog explains the purpose of the review and summarises the key findings.

What is the National Flood Resilience Review?

The UK government’s National Flood Resilience Review (NFRR) was established following the devastating 2015/16 winter floods, where record levels of rainfall saw a number of areas, including Cumbria, and Yorkshire hit by extreme flooding. With the possibility of seeing similar or worse events again over the next decade, the intention of the review published last week was to assess how the nation could be better protected from future flooding and extreme weather events, and also to make recommendations on how previous approaches to the assessment and communication of flood risk could be improved upon.

Action already taken includes a £2.3bn investment from 2015-2021 to improve flood and coastal defences, which will better protect 300,000 homes, and the creation of Flood Re will ensure that households continue to have access to affordable flood insurance.

The approach to flood risk management

In light of recent extreme flooding, it is appropriate to reconsider how we assess flood risk, what actions we take to reduce the likelihood of flooding, and how we can cost effectively improve the resilience of key assets. An important area for improvement is the manner in which we manage rainfall in the natural environment. There are clear benefits to managing water in a way that reduces flood risk, by slowing the flow of water from land to rivers and smoothing the overall flow of rivers. The Government’s 25-year plan aims to achieve this by managing whole river catchments intelligently, and sophisticated models will be developed to understand how flooding in each part of the catchment can be minimised.

Flood models and risk maps

With climate change predictions suggesting that events previously considered extreme are going to become more and more likely in the future, it is important that the appropriate tools are in place to determine which locations are at risk of flooding. Assessing flood risk requires accurate flood models and flood risk maps; as part of the NFRR, the models and maps used in flood risk assessment were stress tested to ensure they could deal with extreme but plausible events, thereby providing reassurance on any predictions of flood risk at given locations.

Understanding fluvial and coastal risk

In order to measure and test the resilience of infrastructure to river and coastal flooding, the Met Office developed a number of new plausible extreme rainfall scenarios. For each of the six climatological regions in England and Wales, additional uplifts to these scenarios, ranging from 20-30%, were determined through modelling and analysis of monthly rainfall records. At the 90% confidence level, it was concluded that the resultant monthly rainfall values have a 90% confidence that they will not be exceeded within the next 10 years, across any of the six regions.

These extreme rainfall scenarios were used within a sample of the Environment Agency’s flood models to predict associated flooding, and the resultant flood extents were analysed. These extents did, however, remain within the EA’s current Extreme Flood Outlines (EFOs), even when combined with extreme tidal surges, and are thus a good representation of extreme but plausible river and coastal flooding.

Infrastructure resilience for key assets

Since the EFOs are a good representation for the most extreme events, they can be used to test the resilience of key infrastructure assets, such as energy, water, and health, which communities and businesses depend upon. Plans are now in place for the water and telecommunications industries to develop and implement, by Christmas 2016, temporary improvements to their resilience, to the level of flooding portrayed in the EFOs. This will bring them in line with the electricity supply industry.

In the 2016 Budget, spending on flood defences and resilience was increased by £700m, in line with previous predictions on the investment needed to maintain existing defences. Findings from the review will see £12.5m earmarked for increasing the EA’s stock of temporary flood defences, and additional funding support will be given as further findings from the review emerge.

Longer term plans are to be developed for permanent improvement of resilience up to the level of flooding given by the EFOs. This can be achieved through increased interconnectivity, enabling services to be rerouted in the event of asset loss, or through installation of permanent defences at significant sites. The EFOs can also be used to test the resilience of core cities, and ensure that decisions made in the next round of flood defence investment (post-2021) are based on the best evidence available.

Also important is learning lessons from past events regarding emergency response and recovery efforts. Actions set out within the review to improve flood incident response include investment in temporary flood barriers, mobile water pumps, and ensuring national assets are at peak capacity in time for winter. There will also be a long-term rolling programme of modelling improvements, including a more integrated approach to flood risk modelling, and improvements to the manner in which flood risk is communicated.

Conclusion

The 2015/16 winter floods demonstrated the devastating effect extreme flooding can have on regions in terms of both disruption and economic losses. With such extreme events predicted to become more likely as a result of climate change, it is imperative that we have not only the tools to model possible future scenarios, but also the framework and investment to ensure the resilience of key infrastructure assets.

After the initial delay of this review Ambiental is delighted to see it published in time to allow for the findings to be turned into action, so as to ensure that the nation is well prepared for potential flooding this winter and beyond. The document is comprehensive in scope and is underpinned by robust scientific knowledge captured through engagement with key industry organisations, which included contributions from Ambiental.

It is encouraging to see that the review identifies the need for wider use of digital tools which is very much part of Ambiental’s core purpose. Our high precision flood maps can identify at risk locations and our innovative work in the field of modelling future climate change scenarios will ensure that any increases in the extent and severity of flooding are well understood. Our flood monitoring from space service for UK government and emergency responders as well as our capability to analyse floods using UAV/drone based surveys will help ensure that the nation has the necessary tools to manage flood risk and protect lives and property. For more information on how Ambiental can advise and support you with your flooding concerns contact us.

The author would like to acknowledge contributions to this blog from Phil Townsend, Ambiental’s PhD research apprentice.