The National Flood Hazard Climate Change maps are based on generalised modelling only.  These maps use the same base information as the Present Day Hazard Maps, but include an allowance for Climate Change (2120).  These maps have no official status for Planning or Insurance purposes, therefore the public and professionals are advised to use the information contained within the Flood Risk Assessment Wales Map and the Flood Map for planning (as appropriate) for these purposes as these will be more up-to-date and incorporate improved modelling information. 

The National Flood Hazard Map for Climate Change have been created for 3 sources of flooding, namely,

1. Flooding from Rivers
2. Flooding from the Sea
3. Flooding from Surface Water & Small Watercourses

The Maps show flood depth, velocity (speed), hazard and extent for High, Medium and Low risk scenarios with raised flood defences. 

For Rivers and Surface Water & Small Watercourses, High risk is up to 1 in 30year plus climate change uplift (CC); Medium risk is between 1 in 30 plus CC and 1 in 100year plus CC and Low risk is between 1 in 100 year plus CC and 1 in 1,000year plus CC Annual Exceedance Probability (AEP).

For the Sea, High risk is up to 1 in 30 year plus CC; Medium risk is between 1 in 30 plus CC to 1 in 200 year plus CC; and Low risk 1 in 200 year plus CC to 1 in 1000 year plus CC.

The Climate Change uplift values use the “Central” estimate for the year 2120 from the Welsh Government guidance available at the time of modelling (2018).

More information about the maps can be found in a briefing note, available on the download link below

Acknowledgments

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