- Are waves included in the Coastal Flood Boundaries?
- Coastal Flood Boundaries - additional help and further information
- How are levels within ‘Inland Extensions’ or ‘Estuaries’ derived?
- How can I generate my Base Tide Curves?
- How does the Coastal Flood Boundaries inform us about flood risk around the UK coast?
- How is sea level rise accounted for in the Coastal Flood Boundaries?
- How often is the Coastal Flood Boundaries dataset updated?
- How should I use Coastal Flood Boundaries levels in estuaries and tidal rivers?
- I am concerned about the large differences in values in some locations and the effects on my project
- I’ve been given mean high water springs (MHWS) and highest astronomical tide (HAT) predicted Tide Levels by another source. They don’t match up to those in the Coastal Flood Boundaries. Which should I use?
- Levels have fallen in my area of interest since the previous Coastal Flood Boundaries update. How can this be when sea levels are known to be rising?
- What are the Coastal Flood Boundaries?
- What are the key outputs of Coastal Flood Boundaries 2018?
- What has been done to update the Coastal Flood Boundaries in 2018?
- What has changed in Coastal Flood Boundaries 2018?
- What information is included in the extreme sea levels shapefiles?
- What is meant by Annual Exceedance Probability (AEP) and which extreme sea level probabilities are included?
- What is the accuracy of the Coastal Flood Boundaries extreme sea levels?
- What is the base year for Coastal Flood Boundaries levels?
- What is the vertical datum of the Coastal Flood Boundaries Level?
- Where can I access the Coastal Flood Boundaries data and guidance documents?
- Who should use the Coastal Flood Boundaries (CFB) data?
- Why are regular updates, and therefore likely change in the estimates, necessary?
Levels have fallen in my area of interest since the previous Coastal Flood Boundaries update. How can this be when sea levels are known to be rising?
Created : 03 October 2019 Updated : 03 October 2019
Sea level rise was included to ensure the levels are relevant to base year 2017 and equates to increases in the order of approximately 2cm at most UK locations. Had the previous CFB levels not changed, base year 2017 levels would all be bigger than the 2011 published levels due to sea level rise differences between base years. However, improvements to the methodology and data has offset small changes in extreme sea levels due to sea level rise. These include:
Significantly longer gauge records available in some areas than for the previous CFB. This can affect the magnitude of any given design level. (also slope of projections may be flatter – therefore low AEP events lower than previous CFB).
Different methodology or process used to derive the levels.
Detailed local study carried out since previous update.
More significant changes due to sea level rise are expected over longer return periods, for example to 2050 or 2100. Sea level rise should be taken into account when predicting flood risk in future years beyond 2017. Information on this is provided in the supporting documentation: Coastal flood boundary conditions for the UK: update 2018, User report.