Causes and effects of flooding (Edexcel GCSE Geography A): Flashcards
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14 cards from this deck
When does river flooding occur?
When does river flooding occur?
Water levels rise above normal bank level
Effect of heavy rainfall on infiltration
Effect of heavy rainfall on infiltration
Ground saturates, can't absorb more water
Overland flow (surface run-off)
Overland flow (surface run-off)
Water flowing over surface into rivers
Impermeable rocks (e.g. granite) & flooding
Impermeable rocks (e.g. granite) & flooding
Prevent percolation, increase surface run-off
Percolation
Percolation
Water seeping downwards through rock layers
Snowmelt effect on flooding
Snowmelt effect on flooding
Sudden release of large water volumes in spring
Drainage basin features raising flood risk
Drainage basin features raising flood risk
Steep-sided valleys & many tributaries
Human activities' main effect on flooding
Human activities' main effect on flooding
Increase surface run-off to rivers
Physical effects of flooding
Physical effects of flooding
Landslides, soil erosion, habitat damage, water contamination
Human effects of flooding
Human effects of flooding
Death, disease, property damage, livelihood loss
Flood hydrograph
Flood hydrograph
Graph showing river response to rainstorm over time
Lag time
Lag time
Time between peak rainfall & peak discharge
Short lag time indicates
Short lag time indicates
Higher flood risk, water reaches river rapidly
Steep rising limb on hydrograph means
Steep rising limb on hydrograph means
Rapid increase in river discharge levels