The probable impacts of climate change on poverty - UNDP

5.4.1 Changes in Flood Frequency
Flood is a regular natural disaster occurring in Bangladesh and thus entailing huge damage to the economy.
Four main types <strong>of</strong> natural floods occur in Bangladesh:
Table 5.7 Different types <strong>of</strong> flood occurring in Bangladesh
Type <strong>of</strong> Flood
Flash Flood
Rainwater flood/
Monsoon Flood
River Flood
Coastal Flood
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Causes <strong>of</strong> occurrence
Run-<strong>of</strong>f durin gexceptionaly heavy
rainfall occurring in neighboring
upland areas
Heavy rainfall occurring over flood
planeand terrace areas within
Bangladesh.
Snow melt in high Himalayans,
Heavy monsoon rainfalls over the
Himalayans, the Asam Hills,
theTripura Hills and the Uppar
Brahmaputra and Ganges flood
plains
In case <strong>of</strong> important cyclones the
entire coastal beltis flooded.
Coastal areas are also subjected to
tidal flooding
Source: Ahmed, 2006
<strong>The</strong> projected increase in rainfall during
monsoon would be reflected in the flow
regimes <strong>of</strong> the rivers <strong>of</strong> Bangladesh. Increased
flooding and drainage congestion, therefore,
are the expected consequences from a warmer
and wetter condition. <strong>The</strong> increased run<strong>of</strong>f
would also aggravate the existing drainage
problem and create new ones. Bangladeshi
rivers, especially the major ones, have lost
gradient during the past several decades.
Consequently their conveyance capacity has
diminished significantly. Furthermore, snow
melting in the Himalayan region along with
simultaneous rise in sea level will eventually
result in prolonged and devastating flood.
From historical point <strong>of</strong> view, it has been
observed that the frequency, intensity and
magnitude <strong>of</strong> flood have increased as well.
Since 1954, 48 small, medium and big floods
have struck Bangladesh. Among those, 7 events
were severe where more than 30% <strong>of</strong> land area
was inundated. <strong>The</strong> following table shows
flooded area from 1954 to 2007.
Time/duration Tentative affected area
Pre monsoon months <strong>of</strong> April and
May
April-May, June-August
April-May andJune-September
Tidal flood occurs from Juneto
September
<strong>The</strong> foot <strong>of</strong> the Northern and
eastern hills <strong>of</strong> Bangladesh
In thesouth-western part <strong>of</strong> the
country
Catchment areas<strong>of</strong> three
majorrivers.
South western coastal areas.
<strong>The</strong> Probable Impacts <strong>of</strong> Climate Change on Poverty and Economic Growth and
the Options <strong>of</strong> Coping with adverse Effect <strong>of</strong> Climate Change in Bangladesh