Assessing your risk

Flooding is a natural event which becomes a threat when lives and property are at risk. The most common cause of flooding is when the river catchment, the area of land that feeds water into the river, receives greater than usual amounts of water. This can occur through heavy rainfall or melting snow. The river cannot cope with this extra water, causing the river level to rise and a flood to take place.

Flooding can also occur from a number of other sources:

• The sea – High tides, storm surges and waves breaching defences can cause flooding in coastal areas.
  
  
• Overland flow – This occurs when heavy rain falls on saturated ground, where water levels are already high or on paved areas, where drainage is poor.
  
  
• Rising groundwater – Groundwater flooding occurs when rainfall causes an underground water table to rise to the surface of the land, flooding low-lying areas.
  
  
• Blocked drains and sewers – Flooding can occur at times of heavy rainfall, where the drains have become blocked or overloaded.
  
  
• Broken water mains – Burst water mains usually cause flooding underground and to basements of properties.

Before considering ways to protect your property against flooding, it is vital to assess the risk of flooding to it. Once you understand the level of flood risk to your property, you can make more effective decisions about the type of flood protection measures to install.

Consider:

• Is your property near a river, stream or ditch?
• Is the land in a hollow or at the bottom of a hill where floodwater could collect?
• Is the area at risk from flooding from the sea?
• Is the area at risk from groundwater flooding?
• Do river or coastal flood defences protect your property?

There are also a variety of sources that you can use to obtain the history of flooding in your area:

• Ask friends and neighbours who have lived in the area for a long time if they know of any flooding incidents that have occurred there.
  
  
• Visit your local library or search online for old photographs and newspaper articles.
  
  
• Speak to your local authority/building control body. They will have documents and plans on flood defences and land use. They will also be able to tell you if flooding has occurred in the area in the past.
  
  
• You can view our online flood risk maps here.