Flooding
of
Bangladesh
2007
–
Case
Study
Location
and
background
of
Bangladesh
:
80%
of
the
country
occupies
one
of
the
largest
delta
systems
in
the
world
and
is
criss-‐crossed
by
thousands
of
small
rivers,
creeks
and
canals.
low
lying
land
.
Moonsoon
rains
-‐
South
of
Himalayas
Cause
of
flood
(
specific
data/detail)
:
Human
Physical
Flash
floods.
caused
by
heavy
rainfall
Two
major
Himalayan
rivers
that
in
and
flooding
of
Indian
rivers,
.
due
empty
into
the
bay
of
Bengal
had
risen
to
the
conversion
of
forest
to
row
alarmingly
crops
which
decreases
interception,
decreases
water
retention
and
increases
the
rate
of
surface
run
off.
Attempts
to
decrease
flooding
by
River
floods.
Snow
melt
in
the
high
building
embankments
and
polders
Himalayas
(
from
the
glaciers)
have
prevented
the
back
flow
of
flood
combined
with
monsoonal
rain
leading
water
into
the
river,
actually
causing
to
peak
discharges
in
all
three
of
the
drainage
congestion
and
back
flooding.
major
rivers
Deforestation,
which
increases
surface
Heavy
rainfall
on
the
hills
and
flood
runoff,
and
decreases
infiltration
and
plains,
outside
the
monsoon
season,
interception
rates.
Urbanisation
has
caused
increased
Storm
surge
floods.
These
are
caused
surfact
runoff,
less
infiltration
,
and
by
cyclones
and
hurricanes
entering
floodplain
storage
space
after
flooding
the
Bay
of
Benga
,Social
Impacts
Economic
Impacts
Environmental
Impacts
10.5
Mio
people
have
The
cost
to
infastructure
The
agriculture
ministry
been
displaced
or
and
housing
is
not
yet
estimated
that
$290
million
marooned
by
the
floods.
determined.
worth
of
crops
had
been
damaged
in
the
initial
flooding.
959
deaths
from
2.2
mio.
tons
of
rice
Over
1mio.
km2
area
flooded
diarrhoea,
drowning,
production
lost
landslides,
snakebites
and
respiratory
diseases
14.000
schools
flooded
75%
of
country
affected
Farm
land
destroyed
15,900
km
of
trunk
roads
26500
livestock
lost
Embankments
cause
damages
(
cattle
and
goats)
wetlands
to
dry
out,
leading
to
loss
of
biodiversity
Building
of
Over
5000
industrial
Decreasing
flooding,
will
embankments
leads
to
buildings
flooded
“capture
fishery”
which
is
displacement
of
people
important
for
protein.
Response
:
Flood
Action
Plan
Bangladesh
with
a
population
of
140
mio.
has
sought
an
initia
$150
million
from
donor
agencies,
with
$60
million
pledged
as
immediate
food
and
medical
assistance.
Saudi
Arabia
alone
promised
$50
million
plus
shipments
of
food.
The
Bangladesh
floods
cannot
be
stop,
but
the
aim
is
to
minimise
the
damage
and
maximise
the
benefits
of
the
floodwaters
and
to
ensure
that
the
discharges
of
the
three
great
rivers
reach
the
Bay
of
Bengal
with
minimum
harmful
effect.
The
embankments
built
are
meant
to
provide
control
of
flooding,
however
cannot
withstand
massive
floods
such
as
in
1987
and
1988
The
embankments
are
set
back
from
the
rivers,
essentially
to
protect
them
from
the
erosive
power
of
the
rivers.
Critique
of
embankments,
despite
foreign
aid
has
created
much
opposition
toward
flood
control.
Conclusion
:
The
Food
Action
Plan
relies
upon
the
establishment
of
a
series
of
embankments
which,
although
not
designed
to
withstand
catastrophic
flood
events,
are
meant
to
give
villages
control
over
the
speed
of
most
flooding
events.
However,
this
approach
has
many
critics
who
believe
that
establishment
of
embankments
along
thousands
of
miles
of
these
rivers
will
cause
serious
social,
economic
and
environmental
problems.
, Identify
similarities
and
differences
between
the
causes
of
floods
in
Boscastle
and
Bangladesh.
Both
floods
occurred
due
to
a
very
large
amount
of
precipitation
flooding
the
village
of
Boscastle
in
the
UK,
and
two-‐thirds
of
the
country
in
Bangladesh.
In
the
case
of
the
Boscastle
flooding,
the
rainfall
was
intense
and
resulted
in
a
flash
flood
which
affected
a
small
area
of
20Km2.
On
the
contrary,
prolonged
and
heavy
rainfall
(
the
Monsoon)
in
Bangladesh
caused
a
reoccuring
flood
to
occur
which
was
fed
by
rivers
draining
a
massive
area
of
1.5
million
km2.
Boscastle
and
Bangladesh
are
both
located
in
an
area
of
a
delta
where
several
streams
or
rivers
confluate,
and
therefore
create
a
dense
stream
network
which
is
more
likely
to
flood.
Both
floods
where
affected
by
human
settlement
near
floodprone
areas,
such
as
the
coast
(
in
the
case
of
Boscastle)
and
the
floodplains
(
Bangladesh),
which
increase
surface
runoff
and
decrease
infiltration.
Human
factors
had
a
bigger
influence
on
the
flood
in
Bangladesh
where
deforestation
and
river
management
decreased
interception
and
prevented
infiltration,
while
physical
factors
such
as
steep
slopes,
impermeable
rocks,
temporary
landslides,
and
a
coincidence
of
high
tide
were
the
apparent
factors
causing
the
flood
in
Boscastle.
While
urbanisation
in
Boscastle
decreased
infiltration
by
its
naturally
impermeable
rock
surface
and
risk
of
drainage
pipe
overflow
(
due
to
sudden
intense
precipitation
following
two
weeks
of
anticedent
rainfall).
Bangladesh
has
agricultural
land
drains,
in
areas
of
permeable
soil,
which
are
affected
or
destroyed
when
human
settlement
on
floodplains
occurs.
Because
infiltration
can
no
longer
occur
,
and
water
can
no
longer
drain
from
the
floodplains
into
the
river
channels
due
to
urbanisation,
flooding
and
damage
of
the
area
is
more
likely
to
take
place.
While
the
flood
in
Boscastle
was
due
to
local
physical
and
human
factors,
the
flood
in
Bangladesh
was
largely
affected
by
the
90%
of
rivers
in
the
delta
located
outside
of
the
borders
of
the
country,
flooding
a
much
larger
area
and
affecting
countries
next
to
Bangladesh
as
well.
In
both
cases
the
floods
were
not
unique,
and
a
flood
had
occurred
in
both
areas
before,
even
though
the
flood
in
Bangladesh
is
more
frequent
event
expected
to
occur
every
year
in
the
Monsoon
season.
Both
examples
focus
on
negative
aspects
of
flooding.
Suggest
some
positive
impacts.
Floods
will
deposit
sediment
and
material
on
banks
and
floodplains,
providing
nutrients
to
soil
and
vegetation.
In
Bangladesh
sediment
is
deposited
on
the
floodplains,
with
large
benefits
for
agriculture,
and
it
rejuvenates
and
saturates
soils
which
have
been
hard
and
dry
due
to
lack
of
anticedent
precipitation.
In
Egypt
people
also
use
the
River
Nile
flood
to
their
advantage,
cultivating
floodplain
areas
which
are
enriched
by
rich
silt
in
which
crops
can
grow.
Floods
replenish
and
renew
groundwater
flow
and
may
create
ponds
or
side
channels,
where
fish
can
live,
and
provide
food
for
inhabitants.
Events
of
flooding
also
increase
the
awareness
of
human
impact
on
rivers
and
river
management,
and
precautions
may
cause
people
to
settle
further
away
from
rivers
and
floodplains,
so
the
floods
can
flow
over
a
larger
area
and
cause
less
damage.
As
well
as
increasing
growth
of
vegetation
and
improving
infiltration
rates,
floods
promote
biodiversity,
and
keep
the
river
healthy.
Hydroelectricity
may
profit
from
flooding,
and
dams
and
other
structures
can
make
use
of
a
powerful
mass
of
water
(flood)
to
add
electricity
to
power
technology.
Periods
of
flooding
may
also
benefit
communities,
which
cooperate
to
prevent
damage
from
flooding.
Helping
neighbours
and
protecting
streets
or
buildings
from
a
flood
creates
a
sense
of
community
in
a
town.
