Geography - Flooding Flashcards
Mumbai
-in 2005, floods caused 700 million in damage
Bangladesh - SLR
A 1m SLR will flood over 11% of the whole country
Deforestation causing flooding
Deforestation in upper drainage basin in Nepal, increased rate and amount of runoff, causing flooding in Bangladesh
Flooding - due to rainfall
70% of Indias rainfall comes of the 100days of summer monsoon
Flooding - cyclones
Hurricane mitch in central America - rainfall intensity of 100mm/hr, killed almost 100,000 people
Bangladesh - Flooding
- 18% of country flooded every year, killing more than 5,000 people, destroying more than 7 million homes
Urbanisation causing flooding
Streamflow in Marcer creek – an urban stream in western Washington had a higher peak discharge and volume than a nearby rural stream
Human flooding
depends on how humans construct the flood channels and engineer it to convey the floodwater quickly
Evaluation
depends on the vulnerability and nature of the affected community
- e.g. high aged population
levee failure
1993 Mississippi flooding
- Re-sectioning
- lined channels
- deepening/widening river channel to increase storage capacity - usually a trapezium shape , but, it leads to higher velocity downstream
Evaluation
hard engineering limitation – due to the finiteness of the effectiveness, will not work if flood is more than expected
very costly, UK spends more than 320 million pounds per year
Afforestation
in the upper misses drainage system
Flood prediction
used in the 1993 mississpi floods
not effective for flash floods
main limitation - time lag
Flood prediction in sg
PUB installed 205 sensors in key canals
