As a part of their study of rivers in GCSE Geography students will look at flooding. This is the second of two quizzes on that topic and it looks at both the risk of floods and their management.
Flooding is a natural part of the yearly cycle of a river, creating flood plains, levees and various other features. Floods occur when the discharge volume of the river becomes too large for the channel to contain. They are commonly seasonal, as in the UK where in winter a combination of frozen, sodden ground and higher than average rainfall will lead to a river going into spate before overtopping its banks and causing a flood.
Before the Neolithic Age, during the winter hunter-gatherer populations would have retreated to higher grounds, only returning when the risk of flooding had passed. In later times we began to attempt flood management. In the 3rd and 4th millennium BC humans started creating canals, dams and channels to try and control the flow of the river. Since then we have been trying to manage and control river flow to prevent flooding. Until recently hard engineering systems were used, but lately the value of soft engineering to reduce the flood risk has been realised.