Flooding Flashcards
Why does flooding happen?
When the level of river discharge gets so high that it spills over its banks
Why does prolonged rainfall cause flooding?
Soil becomes saturated, rain can’t infiltrate increases run off increases discharge
Why does heavy rainfall cause flooding?
Increased surface run off which increases discharge quickly and caused flood
Why does snowmelt cause flooding?
When a lot of snow or ice melts it means that a lot of water goes into rivers in a short space of time which increases discharge quickly and causes a flood
Why does relief cause flooding?
If a river is in a steep sided valley then water will reach river channel much faster because water flows quicker in steep slopes which increases discharge
How can deforestation cause flooding?
Trees intercept rain water in leaves which evaporates, trees take up water from ground and store it. Cutting down trees increases volume of water reaching channel and increases discharge
How can building construction make flooding more likely?
Buildings are made from impermeable materials increases surface run off and drain fake run off to rivers quickly which increases discharge quickly and can cause a flood
