River Flooding Chapter Notes | IGCSE Oxford Geography Foundations for Year 6 - Class 6 PDF Download

What Causes a River to Flood?

Flooding occurs when a river receives more water than it can channel within its banks, often due to heavy rainfall or rapid snowmelt. The excess water spills out onto the floodplain, causing what we know as a river flood. Several factors contribute to this overflow:

• Ground Conditions: If the soil is already saturated from previous rainfall, it cannot absorb more water, leading to runoff into rivers. Conversely, soil that’s too dry can form a hard crust, which also prevents absorption and increases surface runoff.

• Topography: The shape of the land plays a crucial role. Rain falling on steep slopes will rush down much faster, reducing the time for it to soak into the ground and increasing the volume of water that reaches the river, raising the risk of flooding.
• Human Activities: Deforestation removes trees that intercept rainfall and absorb water through their roots, while urbanization replaces permeable ground with impermeable surfaces like concrete, which leads to more runoff. Both activities significantly heighten the flood risk.

How Does the UK Cope with Floods?

The UK faces serious challenges from flooding, with millions living in areas at risk from river or sea floods. To cope with this threat:

• Monitoring and Prediction: Agencies like the Environment Agency in England monitor rainfall, river levels, and sea conditions around the clock. This data helps predict potential floods, allowing for timely warnings and advice to be issued to the public.
• Regional Management: Different regions like Scotland, Wales, and Northern Ireland have their respective authorities, such as SEPA and Natural Resources Wales, managing flood risks and responses.

How Can the Risk of Flooding Be Reduced?

While it’s impossible to prevent flooding entirely, the UK employs various strategies to mitigate the risks and impacts:

• Afforestation: Planting trees can slow down the flow of water, reducing the speed at which it reaches rivers.

• Engineering Solutions: These include constructing embankments to contain rivers, building dams to control water flow, and dredging to increase river capacity.
• Urban Planning: In cities, concrete linings and straightened river channels help manage excess water, directing it away from populated areas.
• Controlled Flooding: Sometimes, allowing certain areas to flood in a controlled manner can protect more vulnerable regions.