Causes and Effects of Flooding (Water) Flashcards
what are the meteorological causes of flooding? (3)
- intense or prolonged rainfall
- monsoon rainfall
- snowmelt
how can intense or prolonged rainfall cause flooding?
a series of midlatitude depressions passing over the same place can cause a build up of river. the ground may intially absorb the water, but throughflow and groundwater flow cannot transfer the water quickly enough for the ground to become saturated. then the only transfer is runoff.
how can monsoon rainfall cause flooding?
warm, moist air blows towards india, sri lanka, bangladesh and Myanmar, bringing terrentail rainfall. this happens because the ITCZ moves northwards and the warm, moist air follows it
how can snowmelt cause flooding?
rapid rises in temprature causes rapid snowmelt, resulting in increase surface runoff and flash floods
what are human causes of flooding?
- changing land use
2. mismanagement of rivers
how does changing land use causes flooding?
vegetation removal for development can increase runoff. deforestation reduces interception and evapotranspiration therefore more runoff so water reaches river channel faster.
Socio-economic impacts of Hurricane Katrina (4)
- 1800 deaths
- $108 billion in damage
- 80% of New Orleans flooded
- By 2014, the number of homes and buisnesses had not reached pre-2005 levels
What happened to flood protection during Hurricane Katrina?
50 failures of levees and flood walls protectin New Orleans, with 20 breeches along the Mississippi
What have investiagators concluded caused extensive flooding in New Orleans?
inadequate design and construction of levees and flood walls by the Army Corps of Engineers
What was the result of the flood wall breeches during hurricane Katrina?
flood water was allowed to flood into the city even though water levels never reached the height of the wall
What were the metrological causes of the 2007 UK summer depressions?
- Unseasonablly low pressure due to the movement of the jet stream
- no recession time due to two consecutive months of rain
Human causes of the 2007 UK summer depressions?
- urban development
2. river mismanagement
How did urban development cause the 2007 UK summer depressions?
- building on flood plains
- 10,000 homes built per year
- 5.2 million properties at risk - urbanisation
- impermeable surfaces
How did river mismangement cause the 2007 UK summer depressions?
- no flood defences
2. Tributaries squeezed into culverts leaving little space to expand during flooding
How many homes in the UK were flooded during storm Eva?
9000
How much damage did storms Desmond and Eva do to the UK?
£5.8 billion
What caused storms Desmond and Eva?
low pressure systems brought by a meander in the jet stream which brought mild, moist air
What were the metrological causes of flooding in Canada 2017?
unseasonably high temperatures causes snow to melt and increase in river discharge
What were the human causes of the flooding in Canada 2017?
Canada’s rate of warming is twice that of the global rate
Socio-economic impacts of Snowmelt in Canada 2017?
- at least two deaths
- £1.5 billion in damages
- 3600 people evacuated
Example of intense and prolonged rainfall causing flooding?>
November 2013 thunderstorms on the Island of Sardinia caused flash flooding resulting in 18 deaths and $1.14 billion in damage
Example of monsoon rainfall causing flooding?
July 2015 heavy monsoon in Myanmar caused 103 deaths
Example of snowmelt causing flooding?
In 2009, Red River ND USA reached record flood levels as a result of snowmelt
