River Landscapes and Processes- Flooding Flashcards
Flash floods
Floods that happen without warning
5 physical causes of flooding
Prolonged rainfall, heavy rainfall, snow melting, rocks, relief
Prolonged rainfall
Long period of rain, soil saturated, more runoff, increases discharge
Relief
Steep valleys, water reaches the channel quickly, increases discharge
Heavy rainfall
Increase in surface runoff, increase discharge
Snowmelt
Lots of snow melts, lots of water in river quickly, increases discharge
Rocks
Impermeable rocks, no percolation, more runoff, increases discharge
5 Human causes of flooding
Urbanisation, agriculture, industry, deforestation, drainage systems
Urbanisation
Changes land use, more impermeable materials, no infiltration,less runoff
Agriculture
More farming, less vegetation, ploughing, more soil eroded into river
Industry
Factories at mouth
Impermeable surfaces–>more run off, risk of floods
Deepen river for boats–>increase capacity, less floods
Chemical weathering from pollutants
Deforestation
Trees removed for industry, urbanisation etc, less interception, more discharge
Social effects of flooding
Loss of life, due to drowning
Damage to houses and belongings
Environmental effects of flooding
Shortage of food from flooded farmland
Contamination of fresh water supplies
Economical effects of flooding
Communication links can be destroyed
Disruption to gas and electricity supplies