Different types of flood risk

Risk of flooding from rivers

River flooding happens when a river cannot cope with the amount of water draining into it from the surrounding land.

Risk of flooding from the sea

Sea flooding happens when there are high tides and stormy conditions.

Risk of flooding from surface water and small watercourses

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.

Risk of flooding from reservoirs

Reservoir flooding is extremely unlikely to happen.

Use the Flood Risk Assessment Wales map to see flooding that could occur from reservoirs.

The shading on the map shows the worst-case scenario for the area that could be flooded if a large reservoir were to fail and release the water it holds. A large reservoir is one that holds over 10,000 cubic metres of water, equivalent to approximately 4 Olympic sized swimming pools.

The reservoir flood maps do not indicate any likelihood of a flood occurring.

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