Risk of Flooding from Rivers and Sea - Climate Change 1

Risk of Flooding from Rivers and the Sea (RoFRS) shows the chance of flooding from rivers and the sea taking into account the presence and condition of flood defences. It is our main way of communicating flood risk from rivers and sea to the public through our ‘Check Your Long Term Flood Risk’ service on gov.uk. Climate change scenarios have been produced for this dataset to indicate the predicted impacts of climate change on future risk.

While flood defences reduce the level of risk they do not completely remove it. For example, water can flow over the top of the defence, or they can fail in extreme weather conditions or if they are in poor condition. As a result, the RoFRS maps may show that there is risk to areas behind some flood defences.

RoFRS is a probabilistic product, meaning that it shows the overall risk, rather than the risk associated with a specific event or scenario. In externally published versions of this dataset, risk is displayed as one of four likelihood bandings:

High - greater than or equal to 3.3% chance in any given year (1 in 30) 
Medium - less than 3.3% (1 in 30) but greater than or equal to 1% (1 in 100) chance in any given year 
Low - less than 1% (1 in 100) but greater than or equal to 0.1% (1 in 1,000) chance in any given year 
Very Low - less than 0.1% chance in any given year (1 in 1,000) 

Our climate change allowances include anticipated changes to:

- Peak river flow 
- Sea level rise 
- Offshore wind speed and extreme wave height 

The climate change allowances are based on the latest UK Climate Projections (UKCP18) from the Met Office, using the Representative Concentration Pathway (RCP) 8.5.

Our Flood risk assessment: climate change allowances include several different allowances reflecting the range of possible future climates. They also provide allowances for different periods of time, acknowledging that some users will want to look further into the future than others. The periods of time vary for each source of risk because equivalent datasets for each source are not always available.

Check Your Long-Term Flood Risk is aimed at supporting individuals, communities and organisations making short- and medium-term decisions to manage future flood risk. We have therefore chosen:

- the ‘Central’ allowance for the 2050s epoch (2040-2069) for risk of flooding from rivers 
- the ‘Higher Central’ allowance for risk of flooding from the sea, accounting for cumulative sea level rise to 2065 

This data also presents the likelihood of flooding for the following depths:

0.2m 
0.3m 
0.6m 
0.9m 
1.2m 

NB. This is a complex dataset, with preview available only on certain zoom levels. The Web Mapping service has been set to 1:50 000 in the <MaxScaleDenominator> attribute. The services are set to be visible from the 1:50 000 scale range. There may be some variation, since end client software may interpret the request differently.