The collapse of river defences or dams. A change in the land use affecting the stores and flows of water in the drainage basin. Whilst many floods are the result of heavy rain, snowmelt or high waves and tides, human activity often contributes to some of the most devastating floods. Engineers constantly seek to control the flow of rivers by building embankments, dams and reservoirs or by straightening their courses. Environmentalists argue that this makes flooding worse because it interferes with the natural flow of rivers.
Deforestation increases surface run-off, causing river levels to rise more quickly.
Soil is washed into rivers more easily, making the channels shallower Move on Read this example of an exam question on flooding. Describe the effects on people of a flood event you have studied. Explain the influences of nature and people on this flood. Happening hints Note the number of marks for this question. For this number of marks it will be important to write an extended answer.