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High risk of flooding from surface water

Surface water flooding happens when rainwater does not drain away through the normal drainage systems or soak into the ground, but lies on or flows over the ground instead.

The shading on the map shows the risk of flooding from surface water in this particular area.

The location you have selected is in an area that has a high chance of flooding from surface water.

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What does ‘high’ mean?

High means that each year, this area has a chance of flooding of greater than 1 in 30 (3.3%).

This type of flooding can be difficult to predict, much more so than river or sea flooding as it is hard to forecast exactly where or how much rain will fall in any storm.

This is based on the best information we have available, such as ground levels and drainage.

What is Flood Depth?

This is the estimated depth of the flood water in metres at the peak of the flood. There are 4 bands

  • less than 0.15m deep
  • 0.15m to 0.30m deep,
  • 0.30m – 0.90m deep,
  • greater than 0.9m deep

What is Flood Velocity?

This is the estimate of maximum velocity or speed of the flood water at the peak of the flood. It has 2 bands:

  • less than 0.25 metres per second
  • greater than 0.25metres per second

What is Flood Hazard?

This is a measure of hazard to people. It is calculated from estimates of flood depth, flood velocity and possible debris within the flood water. There are 4 bands for classifying flood hazard to people.

Low – A flood risk area with shallow flowing water or deep standing water.

Danger for Some – A flood risk area with deep or fast flowing water. Dangerous to children, the elderly and the infirm. 

Danger for Most – A flood risk area with deep fast flowing water. A significant hazard to the general public.

Danger for All - A flood risk area with very deep fast flowing water. An extreme risk including emergency services.

Outside the shaded areas on the map, the risk of flooding is 'very low'

The shading on the map shows the risk of flooding from surface water.  All areas outside the shaded area have a very low chance of flooding from surface water. 

What does ‘very low’ mean?

Very low means that each year, this area has a chance of flooding of less than 1 in 1000 (0.1%) for Surface Water.

This type of flooding can be difficult to predict, much more so than river or sea flooding as it is hard to forecast exactly where or how much rain will fall in any storm.

This is based on the best information we have available, such as ground levels and drainage. 

Floods destroy - be prepared

Don’t wait until it’s too late. Prepare for flooding by taking some simple steps to reduce the impact on your home or business.

Further information

The map has been produced by Natural Resources Wales, using information from Lead Local Flood Authorities where it is available. Lead Local Flood Authorities are responsible for managing the risk from surface water flooding.

If you have questions about how the map was produced, please call Floodline on 0345 988 1188.

If you would like more information on how surface water is being managed in this area, you can speak to your Local Authority.

You can use the information in this area to see the areas that would flood, which streets may be at risk of flooding.

This area may be at risk from other types of flooding

For the purposes of the Flood Risk Regulations 2009 and the EU Directive 2007/60/EC on the assessment and management of flood risks, this is a Flood Hazard Map.

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