Impact Assessment of Climate Change and Sea Level Rise on ...

Table E.3: Inundated area in different depth categories in an average flood condition
Districts
Area
L<strong>and</strong> Type (km 2 )
(km 2 ) F0 F1 F2 F3 F4
Faridpur 2072.72
Inundation at 2005 32.04 156.60 289.80 186.57 10.35
Area in % 1.55 7.56 13.98 9.00 0.50
Sirajganj 2497.92
Inundation at 2005 58.23 401.49 699.21 423.90 12.24
Area in % 2.33 16.07 27.99 16.97 0.49
Sunamgan
Inundation at 2005 882.17 371.43 699.48 1178.10 472.95
3669.58
j
Area in % 24.04 10.12 19.06 32.10 12.89
Satkhira 3858.33
Inundation at 2005 35.91 121.50 392.31 1844.37 0.09
Area in % 0.93 3.15 10.17 47.80 0.00
Barisal 2790.51
Inundation at 2005 117.63 975.33 749.43 78.12 0.00
Area in % 4.22 34.95 26.86 2.80 0.00
Gaib<strong>and</strong>ha 2179.27
Inundation at 2005 74.43 414.81 479.79 104.04 0.36
Area in % 3.42 19.03 22.02 4.77 0.02
Pabna 2371.5
Inundation at 2005 61.56 219.96 487.08 553.68 126.18
Area in % 2.60 9.28 20.54 23.35 5.32
E.4 CHANGE OF FREQUENCY OF CHARACTERISTICS FLOOD
Efforts have been made to examine the increase <strong>of</strong> occurrence <strong>of</strong> characteristic flood over the
historical years. Time series water flow <strong>of</strong> Jamuna river at Bahadurabad is available from
1956 to 2007. All the available data have been divided into three parts 1956-73, 1974-1990
<strong>and</strong> 1991-2007 to carry out statistical analysis to investigate the increase <strong>of</strong> number
occurrence <strong>of</strong> a specific flood event. Frequency analysis has been done for each part. From
the analysis <strong>of</strong> first part it has been seen that a flood flow <strong>of</strong> 76,137 m 3 /s has a return period
<strong>of</strong> 25 year which means it may occur 4 times in the next 100 years. In the analysis <strong>of</strong> second
part the same flood flow shows return period <strong>of</strong> 5 year which means that it may occur 20
times in the next 100 years.
From the frequency analysis
<strong>of</strong> third part it has been
found that the return period
for the above water flow is
3.5 year which means that it
may occur 28 times in the
next 100 years. This analysis
shows number <strong>of</strong> occurrence
<strong>of</strong> a particular flood has
increased over the years,
which is shown in the Figure
3.1. This indicates that
severe flood may come more
frequently in future.
However, this needs more
analysis <strong>of</strong> flow <strong>and</strong> rainfall.
Number <strong>of</strong> Probability <strong>of</strong> Occurence in the next 100 year
30
25
20
15
10
5
0
Year 1956 - 73 Year 1974 -90 Year 1991 - 07
Figure E.2: Increase in number <strong>of</strong> occurrence <strong>of</strong> characteristic
flood over the historical years at Bahadurabad.
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