Identifying flood risk

Flood water can originate from a number of different sources. It is important to identify which of these sources of flooding your property or workplace may be at risk from. Information on each of these sources can be found below.


Follow the links to identify which sources of flooding you may be at risk from:

  • Fluvial (main river) flooding is the responsibility of the Environment Agency to manage the flood risk from these sources.

  • Surface water flooding is caused by the build up of storm water on surfaces, often when these surfaces are hard paved, or where rainfall exceeds the infiltration capacity of the soil. Surface water flooding is our responsibility.

  • Ordinary watercourses are smaller brooks and drainage channels which are not defined as main river (see above for main river definition). Managing the risk of flooding from ordinary watercourses is the responsibility of both us and the riparian owner of that watercourse.

  • Groundwater flooding occurs when the water table, the water level below ground, rises above the ground surface. During periods of heavy rainfall, the water level in the ground may rise to such an extent that it floods basements, or emergence of groundwater at the surface may cause damage to properties and infrastructure. Managing groundwater flooding is our responsibility.

  • Reservoir flooding occurs following the failure of structures holding back reservoir water (for example dams, retaining walls). It is the most unlikely source of danger to any property due to the strict regulations and maintenance schedules employed by reservoir operators. 

Information on other websites