What causes flooding? Year 7

Impermeable rock is when ____________

• Rainfall cannot soak through the rock easily

• Rainfall can easily soak through the rock

Impermeable rock causes flooding because ___________

• Rainfall cannot soak through the rock and so it flows quickly into the river, increasing the discharge

• Rainfall soaks through the rock and so it flows slowly into the river, decreasing the discharge

• Impermeable rock is not a cause of flooding, permeable rock is.

Prolonged heavy rain causes flooding because ____________

• The trees intercept the rain, less water flows into the river, increasing the discharge

• Soils become saturated, more water flows into the river, increasing the discharge

• The permeable rocks absorb the rain, more water flows into the river, decreasing the discharge

'Cutting down trees can make flooding more likely'

• True

• False

Deforestation causes flooding because _________

• Steep slopes mean that water runs into the river quickly

• There are no leaves to catch (intercept) the rain and the water reaches the river quickly, increasing the discharge

• Tree leaves catch (intercept) rain meaning that water doesn't flow into the river as quickly

'Built up areas like cities are less likely to flood'

• True

• False

Human-made surfaces (e.g. concrete) can cause flooding because ________

• Humans use lots of water

• They are permeable so the water soaks in, decreasing river discharge

• They are impermeable and water runs into the river quickly, increasing its discharge

Which statement is NOT a cause of flooding?

• Inadequate flood defences

• Planting trees

• Impermeable rock

• Confluence point

Saturated soil causes flooding because __________

• The soil cannot absorb any more water, so more water flows into the river

• They are impermeable and water runs into the river quickly, increasing its discharge

• Tree leaves catch (intercept) rain meaning that water doesn't flow into the river as quickly

Relief is ________

• Where two rivers meet

• How steep slopes are

• If a surface lets water soak through