There are different types of flooding that affect households and businesses around the UK.
- Surface Water Flooding
- Ground Water Flooding
- River Flooding
- Coastal and Tidal Flooding
- Reservoir or Dam Failure
- Burst Water Mains
- Sewer Flooding
The environment agency has a flood risk map on their website that lets you know if you’re in a known flood risk area. It shows areas where surface water flooding, ground water flooding and river flooding are more likely in England. In case you’re not aware of the different types of flooding, I’ve explained the first three in this post.
Surface water flooding occurs in heavy rain. It’s when the rain is prolonged and the drainage system can’t carry the water away fast enough and the water cannot soak into the ground because it is too saturated. Surface water flooding can also occur if drains are blocked. Surface water flooding will flow downhill and collect in low-lying areas.
Groundwater flooding occurs during intense and prolonged periods of rainfall. Groundwater is any water that is found beneath the surface of the ground, filling cracks and pores in the underlying soil and rocks.
At a certain level beneath the ground, the soil and rocks would have become saturated so no more water can be absorbed, this is the ground water level. The soil and rocks between the ground water level and the surface is known as the water table.
The water table’s thickness varies depending on where the ground water level is beneath the surface, and will become thinner as more water is soaked up by the ground. At a certain point, the ground water level will emerge through the surface of the ground causing groundwater flooding.
If groundwater flooding occurs at a high point, when the water levels rise further, above the height of the natural boundaries, the flood water would then run over the ground and will collect at the lower levels on the surface of the ground.
River flooding can occur following heavy rainfall over upstream watercourses where that watercourse is unable to carry the resulting higher flow of water. This type of flooding can extend over very large areas and cause widespread damage.
Visit the environment agencies website to see if you’re at risk. Flood Risk Maps.