3.7.3 Flooding (including Riverine Floods, Flash floods ... · occurring in the year 2006. Further,...
7
3.7.3 Flooding (including Riverine Floods, Flash floods, Urban flood and Heavy rain) 3.7.3.1 Distribution Annual Time Series Distribution Figure 44 shows the occurrence of flooding during the period 1974-2008. Throughout the years it appears to take on a consistent pattern. However, af ter the year 1998, the pattern of flooding has been fluctuating. The incidence of flooding seems to be prevalent in the latter years with most flooding occurring in the year 2006. Figure 44 : Annual Time Series Distribution of Floods Figure 45 : Seasonal Distribution of Floods : 1974 - 2008 100 150 200 250 Number of events 50 Year 1974 1976 1978 1980 1982 1984 1986 1990 1992 1996 1988 2000 2002 2004 2006 2008 1994 1998 0 100 150 200 250 300 350 Number of events 50 0 Month January February March April June May July August October November September December Seasonal Distribution Flooding in Sri Lanka appears to take on a cyclical pattern with peaks at two different points of time as seen from Figure 45. The first peak can be seen in May and thereafter, a second peak can be seen in October, November, December and January. This may be attributable to the patterns of the monsoon. source www.desinventar.lk source www.desinventar.lk 72 Chapter 03 Disaster Event and Impact Profile
Transcript of 3.7.3 Flooding (including Riverine Floods, Flash floods ... · occurring in the year 2006. Further,...
3.7.3 Flooding (including Riverine
Floods, Flash floods, Urban flood and
Heavy rain)
3.7.3.1 Distribution
Annual Time Series Distribution
Figure 44 shows the occurrence of flooding during
the period 1974-2008. Throughout the years it
appears to take on a consistent pattern. However,
after the year 1998, the pattern of flooding has been
fluctuating. The incidence of flooding seems to be
prevalent in the latter years with most flooding
occurring in the year 2006.
Figure 44 :
Annual
Time Series
Distribution of
Floods
Figure 45 :
Seasonal
Distribution of
Floods :
1974 - 2008
100
150
200
250
Num
ber
of eve
nts
50
Year
19
74
19
76
19
78
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80
19
82
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84
19
86
19
90
19
92
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96
19
88
20
00
20
02
20
04
20
06
20
08
19
94
19
98
0
100
150
200
250
300
350
Num
ber
of eve
nts
50
0
Month
Jan
ua
ry
Feb
rua
ry
Ma
rch
Ap
ril
Jun
e
Ma
y
July
Au
gu
st
Octo
ber
No
vem
ber
Sep
tem
ber
Decem
ber
Seasonal Distribution
Flooding in Sri Lanka appears to take on a cyclical
pattern with peaks at two dif ferent points of time as
seen from Figure 45. The first peak can be seen in
May and thereaf ter, a second peak can be seen in
October, November, December and January. This
may be attributable to the patterns of the monsoon.
source
www.desinventar.lk
source
www.desinventar.lk
72
Chapter 03Disaster Event and Impact Profile
Spatial Distribution
With respect to spatial distribution (Map 24), floods
appear to occur mostly in the districts of Kalutara
and also in areas like Ratnapura, Gampaha,
Ampara and Jaffna. With respect to DS divisions,
the highest incidence of flooding appears to occur
in the Western parts of the island, while most other
DS divisions have a low incidence.
3.7.3.2 Impacts
People Affected (Annual Time Series and
Spatial Distribution)
The time trend of people affected appears to have
fluctuated considerably during the period under
consideration (Figure 46). However, it can be seen
that people have been increasingly affected by
floods since 1993, with the highest number affected
in the year 2008. When considering the Spatial
Map 24 :
Spatial
Distribution
of Floods :
1974 - 2008
DS DivisionsDistrict
Distribution (Map 25), people located in Batticaloa
appear to be the most affected by the floods along
with people in Colombo, Gampaha, Rathnapura and
Ampara. Those people located in districts in the
Central part of the island appear to be the least
affected. A similar pattern can be observed with
respect to the DS divisions.
source
www.desinventar.lk
Sri Lanka National Report on Disaster Risk, Poverty and Human Development Relationship
73
Map 25 :
People Affected
Due to Floods
– Spatial
Distribution:
1974 -2008
District DS Divisions
Figure 46 :
People Affected
Due to Floods -
Annual Time
Series
Distribution
1000000
1500000
2000000
2500000
500000
Nu
mb
er
of
pe
op
le a
ffe
cte
d
Year
19
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19
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78
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92
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88
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00
20
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20
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06
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08
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0
source
www.desinventar.lk
source
www.desinventar.lk
74
Chapter 03Disaster Event and Impact Profile
Figure 47 :
Loss of Life Due
to Floods –
Annual
Time Series
Distribution
Loss of Life (Annual Time Series and Spatial
Distribution)
The loss of life due to floods is relatively quite low and
stable over the time period (Figure 47). However, a
large increase in the number of deaths was seen in
2003 as the rain was exceptionally intense during
May 2003, which caused severe floods. People living
Map 26 :
Loss of Life
Due to Floods
– Spatial
Distribution :
1974 -2008
180
20
40
60
80
100
120
140
160
0
Year
Num
ber
of death
s
19
74
19
76
19
78
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80
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82
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84
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86
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96
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98
DS DivisionsDistrict
in the districts of Kalutara, Rathnapura, Jaffna,
Matara and Galle have been most prone to loss of life
due to floods (Map 26). The low incidence of life loss
reflected in a majority of DS divisions across the
island can be attributed to the limited availability of
disaggregated data at the DS division level.
source
www.desinventar.lk
source
www.desinventar.lk
Sri Lanka National Report on Disaster Risk, Poverty and Human Development Relationship
75
Destroyed and Damaged Houses (Annual
Time Series and Spatial Distribution)
Houses destroyed and damaged seem to take on a
fluctuating pattern (Figure 48). However, the most
damage has been caused by the floods that
occurred in 2008. Spatially (Map 27), most of the
damage has taken place in the districts of Ampara,
Figure 48 :
No of Houses
Destroyed
and Damaged
Due to Floods
– Annual
Time Series
Distribution
Map 27 :
No of Houses
Destroyed and
Damaged Due
to Floods
– Spatial
Distribution :
1974 - 2008
No o
f houses d
am
aged a
nd d
estr
oye
d
20000
30000
40000
50000
60000
70000
10000
Year
19
74
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92
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00
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06
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0
Batticaloa, Rathnapura, Jaffna and Polonnaruwa.
Districts such as Nuwara Eliya, Matale, Kandy and
Vavuniya appear to be the least affected. With
respect to DS divisions, most of the damage appears
to occur in DS divisions located in the Southern and
South Western parts of the island
District DS Divisions
source
www.desinventar.lk
source
www.desinventar.lk
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Chapter 03Disaster Event and Impact Profile
Losses to Agricultural Crops (Annual Time
Series and Spatial Distribution)
Most damage to paddy has been observed in the
earlier years, with the worst impact recorded in 1984
(Figure 49). Despite this, losses appear to have been
consistent and low throughout the period under
Figure 49 :
Hectares)
Agricultural
Loss Due to
Floods
(in –
Annual
Time Series
Distribution
review. Spatially (Map 28), most damage has taken
place in the districts of Kurunegala, Polonnaruwa,
Batticaloa, Killinochchi and Ampara, whilst least
damage has taken place in Kandy, Matale and
Nuwara Eliya. With respect to DS divisions, most of
the DS divisions are not severely affected.
Map 28 :
Hectares)
Agricultural
Loss Due to
Floods
(in
Spatial
Distribution :
1974 -2008
–
DS DivisionsDistrict
70000
80000
10000
20000
30000
40000
50000
60000
0
Hecta
res o
f agricultura
l lo
ss
Year
19
74
19
76
19
78
19
80
19
82
19
84
19
86
19
90
19
92
19
96
19
88
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00
20
02
20
04
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06
20
08
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94
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source
www.desinventar.lk
source
www.desinventar.lk
Sri Lanka National Report on Disaster Risk, Poverty and Human Development Relationship
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Box 9 :
Conclusions on
Distribution and
Impacts of
Flooding
The incidence of flooding seems to be most
frequent in the latter years, with the most flooding
occurring in the year 2006. Fur ther, the floods in
Sri Lanka are most likely to occur in the months of
May in the first cycle and in December in the
second cycle. With respect to spatial distribution
floods are most frequent in the districts of Jaffna,
Kalutara, Rathnapura, Gampaha and Ampara.
People have become increasingly affected by
floods with the highest number recorded in 2008.
Further, people located in the districts of
Gampaha, Kalutara, Batticaloa, Rathnapura and
Ampara have been most affected by floods.
However, the occurrence of deaths due to floods
is quite low except for the year 2003 where it
reached nearly 180 persons. Destruction and
damage to houses and buildings also appear to
follow a similar pattern with most damage
occurring in the districts of Rathnapura, Ampara,
Batticaloa, Polonnaruwa, and Jaffna. Damage to
paddy has taken place mostly in the earlier years
with the highest impact recorded in 1984, while
spatially the highest damage has incurred in the
districts of Kurunegala, Polonnaruwa, Ampara
and Batticaloa.
In some instances with respect to DS divisions,
some impacts have been reflected as low, which
can be attributed to the limited availability of
disaggregated data at this level.
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Chapter 03Disaster Event and Impact Profile
