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2012 2nd International Conference on Environment Science and Biotechnology
IPCBEE vol.48 (2012) © (2012) IACSIT Press, Singapore
DOI: 10.7763/IPCBEE. 2012. V48. 16
Identifying the Ecological Effects of Flood on Indus Delta and Its
Coastal Areas
Asma Shaheen Hashmi +, Sadia Qamar, Noureen Akhtar, Khalid Mahmood and S.M. Talha Qadri
University of Sargodha, Sargodha, Pakistan
Abstract. The study is about the after flood effects on the delta region. In Pakistan Indus river makes well
defined delta near Karachi. This river starts off from Mansarovar Lake in Tibet; this location is on the
elevation of 5182 m. The River Indus covers the area of approximately 2880 km downstream and enters the
Arabian Sea while passing through the Indus Delta, which is considered as the fifth largest delta of the world.
The Indus delta covers 653 km coastal area of Sindh province. The shape of Indus delta is fan shaped
triangular and it is on the mouth of river Indus. The delta has its crest to the south of Thatta and dynamic
Indus Delta takes up an area about 600,000 hectares. The Delta of Indus River has vital effects in the
everyday lives of the people, their economy, and ecological interest of the area. Significant amount of water
is required to nourish delta throughout the year. Many environmentalist and agronomist believe that Indus
delta is retreating because at upstream areas significant amount of water is being dammed or preoccupied in
other channels. This research identifies the environmental effect of flood on Indus delta and coast with
respect to physical and ecological variability. The research mainly focuses on some temporal changes in delta
caused by the floods. Some recommendations are also put forward to maintain ecological and environmental
balance which can save the community feeding on delta. Different method of GIS and remote sensing are
used to identify the change in ecology and physical environment of the area. The study is based on pre and
post flood parameters for change detection in delta. The change detection analysis is applied to different
classes of data set used. The data sets include satellite images, field data of mangroves forests, ground water
table depth, soil data and NDVI for vegetation. The research elaborates the high risk areas in terms of
depletion of mangroves as well as fish productivity before flood and comparing any kind of change in above
mentioned parameters after flood. The research further can be extended for the management of delta, coastal
areas and a Spatial Decision Support System can be developed to deal with changing climatologically
conditions and sea level change.
Keywords: Mangroves, Delta, Indus River, Ecology, Flood
1. Introduction
Indus is the largest river of Pakistan; it forms fan shaped delta and falls into Arabian Sea. The Indus delta
mangroves covers are the largest area of arid climate mangroves and are 7th heftiest block in the world. The
freshwater inflow is being reduced due to upstream diversion of water, and inflow of pollutants from
different industries, mills, human and livestock waste, sewage water, navigational activities has been
increased. There are some other factors including pressure of increasing population, degradation of trees for
fuel wood and fodder collection have imposed danger which are affecting the complex ecosystem in term of
harsh environmental and social pressures. The degradation of delta is analyzed to assess the danger to
biodiversity, reduction in fish productivity, the loss of other habitats, economic problems related to society
and coastal communities. Indus Delta is facing very serious problem due to the decreasing flow of water, the
brackish water of sea flows toward delta and causes devastation in its ecosystem. Mangroves flourish in
deltaic regions throughout the world, yielding fluvial inflow and fresh water play vital role in their high
growth. Increase in their production is directly proportional to the availability of freshwater and vice versa.
+
Corresponding author. Tel.: +923327547997
E-mail address: [email protected]
81
Approximately from six decades ago there is incessant decrease in the discharge rate of Indus River. Many
barrages and dams are constructed to overcome the agricultural demands. As a consequence very low
discharge is left behind for nourishment of delta. This is the most significant reason of deprivation of Indus
delta in result of which Ecology of the delta, Mangroves and fishes are in danger. Although recent flood in
2010 proved to be very devastating in upper portions of Pakistan yet proved blessing in disguise for Indus
delta. This research paper highlights the temporal changes caused due to flood. There were used different
factors especially pre and post flood discharge, ecology, mangroves and fish to conclude the effect of flood
on Indus delta.
1.1. Methodology
Satellite Images of Landsat 30 meter for pre and post flood are used to assess the vegetation (mangroves)
and change in other classes in delta region of Indus River. NDVI on both images is applied to find out the
variation in vegetation due to flood.
NDVI= IR-R / IR+R
Then Using supervised classification technique land use classes are identified. Reclassify method is
applied to calculate area of each class. Pre and post flood areas are calculated and change was identified.
1.2. Methodology Flow Chart
Satellite Images
NDVI and Land use
classes
(Pre and post flood)
Ecology data
River Discharge
data
Fish data
Lakes and their
Habitat
Temporal
analysis
Kotri Barrage
Downstream
Graphical Analysis
Identify Variance in mangroves
production
Temporal analysis of
discharge
Identify the Threaten area
Fig.1: (a) Pre Flood NDVI
Fig.1: (b) Post Flood NDVI
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Fig.1: (c) Pre Floodd Landuse/Laand Cover
Fig.1: (d) Post Flood L
Landuse/Land Cover
The claassified imagges of delta and
a Normaliized vegetatiion index shhows that theere is signifiicant changee
during pre and post floood time. Veegetation, water
w
bodies and wet soiil increased while small dunes weree
undulated under
u
water and
a decreaseed in numberr. Deposited soil shifted from left baank to right bank
b
of riverr
and increassed in amounnt due to uppstream erosion, less weet soil decreaased due to over flow of
o water andd
converted it into water bodies . Like land use classes therre were also considerablle change in
n normalizedd
difference vegetation
v
inndex (NDVI)), this index shows vegettation health in index nuumbers. There is increasee
in vegetatioon and water class and deecrease in barre soil from pre-flood
p
ND
DVI to post-fflood NDVI
Table 1: Lannd Use Classess of Indus Dellta (Pre and Poost
Flood 20110) Area Km2
K
8000
Land
d Use Classes of
o Indus Delta (Pre and
7000
6000
Land Use Classees
Pre Flood
Postt Flood
Soil Deposition
2900
528
Chaang
e
238
Less Wet Soil
32663
668
-25995
2000
Sand Accumulaation
3400
626
286
1000
Small Dunes
48
16
-32
Vegetation
55223
68055
1285
Water Bodies
31886
37211
535
Wet Soil
23335
26111
276
Coastal Depositts
0
9
9
5000
4000
Pree Flood
25883
94336
29666
Post Flood
0
Fig. 2: Grraph showing lland use/cover changes
c
Table 2: NDV
VI Classes (Pre and Post Fllood 2010) Arrea
K 2
Km
NDVII Classes
Waterr Bodies
Bare Land
L
Vegetaation
Pre Flood
3000
NDVI Deriven Classes
010)
(Pre Flood 20
20
2
%
Postt Flood
32144
75855
42877
Water
Bodie
s
Bare
Land
63
%
83
17
%
NDVI Derive
en Classes
(Post Floo
od 2010)
29
%
21
%
50
%
Water
Bodies
Bare
Land
Veget
ation
Fig.
F 3: Graphs showing NDV
VI changes in
n pre and post
flood time
2. Effectts of Decrreasing In
nflow on Deltaic
D
Eccosystem
2.1. Decrrease in Discharge forr Deltaic Region
R
The exppanding poppulation withh high growtth rate of alm
most 2.93% and there iss not as mucch rainfall too
fulfill the demand
d
of increasing agricultural
a
land and crrops. The inncreasing groowth of pop
pulation hass
intensified the
t demand of water in all
a sectors inncluding dom
mestic, agricuultural and inndustrial. Th
he maximum
m
water supplly is required in irrigatioon sector forr production
n of food andd raw materrial, as well as water forr
industrial annd domestic use. There are
a different storage dam
ms and barragges that havee been constrructed on thee
Indus and other
o
Rivers and a composite networrk of canals system transsport its wateer to agriculttural land off
about 30 miillion acres. Tarbela Dam
m is also usedd to generatee hydroelectrric power whhile some oth
her dams aree
under consttruction to inncrease the sttorage capaciity for powerr generation,, agriculture and industry
y. In order too
meet the huuman needs water scienntists and enngineers sugg
gest construccting water storage upsttream whichh
depicts their unawareneess or neglectting attitude towards the deltaic regioons. The most of the policies neglectt
the drastic and
a devastatting impact of
o reduced innflow of watter into the delta.
d
As a m
matter of factt fresh waterr
flow has beeen reduced from
f
130 million acre feeet (MAF ) to
o 0.02 MAF in the last 500 years. Whiile in the lastt
decade fressh water releease reachedd to its miniimum level. IUCN has calculated tthat at least 27 MAF iss
essential forr the continuued wellbeingg of the Induus Delta.
Table 3: Shoowing the Proggression of Ind
dus Delta in Eye
E of Historyy
Period
d
Date
Delta Progrression (Miles)
Pre-hiistorical Period
Prior too 3000BC
36
Greekk Period
4th Cenntury BC
16
Arab Period
P
8th Cenntury
6
Middlle Age
12-13 Century
C
AD
2
Kalhoora-Talpur Periodd
18th Century
C
Britishh Period
20th Century
C
0.5
Almost curreent situation
2.2. Declline in Quaantity of Fissh due to Decreasing
D
Discharge
D
Anotherr problem faaced by the Delta was declining
d
tren
nd in fish production. T
This threat em
merged as a
consequencce of over yield
y
of fish possessionss caused by amplified trrend of expport without deliberatingg
existing envvironmental rules and reegulations reegarding fish
h productionn. The Mancchar ecosysteem has thuss
started decllining. Theree fish catches are being decline
d
on teemporal basiis there was 3,000 tons fish
f catch inn
1950, now it
i is only 1500 tons. Beforre 1960 the documented
d
number fishh species wass 400 and theere were 7266
bird speciess, but now att this time thhere are left just
j 70 speciies of fish annd 100 species of bird. Presently,
P
thee
40% of totaal bird popullation has been reduced.
2000
Metrric tonn
Fish
h changing tre
end
Fish in metric tonns
0
1980 1985
1
1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
2.3. Size of Mangrooves
In Pakistan, the totaal area coverred by manggroves is 132
2,000 hectarres, which is 129,000 hectares in thee
Sindh (Induus Delta) andd approximaately 3,000 ha
h on the Co
oastal area of Balochistaan including the areas off
Kalmat Khor, Miani Hor,
H
and Gaw
watar Bay. Therefore
T
th
he Indus Delta contains 97 percent of the totall
f
whereeas the otherr three segmeents on the Balochistan
B
ual 3 percentt
mangrove forest,
Coast includde the residu
(changing from
f
25 perccent in Mianni Hor to 2 percent in Kalmat
K
Khoor and 8 perccent of the total
t
area inn
Gawatar Baay). There was
w significant loss in production of mangrovves during thhe last 60 years
y
on thee
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qualitative as well as quantitative basis in Pakistan. The production of Mangroves has been reduced up to 54%
of all, from this only 31% are vigorous while another 31% are near to die or in dying stage (Memon, 2000).
2.4. Decline in Fertility of Agricultural Land
The ecosystem and economical condition of Indus Delta was badly affected by decreasing flow of
freshwater, and as a result it leaded intrusion of saltwater. The land of this area has turned into inappropriate
for agriculture and crop production, and clean and drinkable water supply is very limited or have vanished
from most of the areas (Zaigham 2002). The Thatta is an important farming District of Sindh Province, Indus
River enters in Arabian Sea near about Thatta, about one third land portion of this district has been
influenced by the invasion of brackish. Sea water intrusion is affecting the fertile land of country and about
0.5 million hectares of productive land in Thatta and bordering areas (IRIN 2001), or up to 12% of total
fertile area of the whole province is turned into ruin land (Government of Pakistan 2001). The loss in fertile
soil caused the decline in crop production and consequently harsh downfall to livestock, lack of fodder, loss
of grazing land, water bodies, and ultimately extensive migration of population and livestock (Salman 2002).
2.5. Increase in Water Pollution
Indus Delta is continuously receiving polluted and contaminated wastes. Major sources of these
pollutants are untreated industrial effluents and agricultural contaminants. The major effluents are Arsenic,
Mercury, Lead, and many other heavy metals these pollutants provide rigorous harm to aquatic life (Amjad
et al 2007). The research reveals that on the coastal surroundings of Karachi approximately 37,000 tons of
industrial effluent and solid waste is being dumped every year, while, annually 20,000 tons of oil reaches to
fishing grounds, coastline and ports of Karachi. The coasts are being polluted due to the eutrophication and
increasing concentration of bioaccumulated toxic contaminants. This situation is being worse with every
passing day and ultimately there would be huge loss of biodiversity and downfall of economy.
2.6. Sea Water Intrusion in Indus Delta
The Saline water of sea has encroached about 64 km of land area, and loss of agricultural lands has
hence been around 1.2 million acres (report by IUCN, 2005). The saline and non-potable water use to enter
the aquifers and consequently, this all area becomes the part of sea. On the basis of some statistics the
regions namely Shah Bunder, lost 590,000 acres, Ghorabari has vanished 31,490 acres, Mirpur Saskro,
60,178 acres, Kharo Chaan, spoiled 117,823 acres, the area of Keti Bunder, 113,900 acres; Golarchi has
misplaced 30,625 acres, Badin, 49,179 acres, and Jati, has lost 226,663 acres of its area (Memon 2005).
2.7. Population and Poverty Increase
The delta is nourishing a very huge part of population and ecology and fulfilling the domestic,
industrial, drinking, agricultural, ecological, and aquaculture needs. The population of only Thatta district is
over 1.1 million. In Indus delta there are very prominent damages regarding social and environmental aspect.
This area was to be considered as very rich land for production of rice and pulses due to well defined
network of freshwater streams surrounded by fertile silt and clay.
2.8. Over all Ecological Disturbance in Indus Delta
The anthropogenic activities have altered the ecosystem of mangroves during last one decade.
Freshwater inflow has been alarming due to the upstream deviation by dams, canals and upstream water
piracy by bordering country. In short Indus flooding is the lifeline for the survival of these ecosystems
without which their sustainability would be at risk. Due to all above mentioned threats to delta scientist and
environmentalist claimed it to be a delta with vanishing ecosystem.
3. Acknowledgements
We acknowledge WWF Lahore, for providing GPS data of Indus delta for completing this research.
4. References
[1] Altaf A. Memon, 2005, Devastation of the Indus River Delta, World Water & Environmental Resources Congress
2005, ASCE, Environmental and Water Resources Institute, Anchorage, Alaska, May 14-19
85
[2] Amjad A.S., Kasawani I., Kamaruzaman J. 2007, Degradation of IndusDelta Mangroves in Pakistan. Int J Geolo
3:27–34
[3] Memon, N., 2000, Damning the delta: Website Lead-Pakistan.
[4] Zaigham, N.A., 2002, Basement controls the rivers flow in southern Indus basin: An analysis of the Indus and Gaj
rivers of Pakistan: Special publication of SEGMITE and NIO on Water, 2002.
[5] Salman, A., 2002, Draft Proposal for Economic Valuation of Mangrove Ecosystem in Pakistan, Prepared for South
Asia Network for Development and Environmental Economics, Kathmandu
[6] IRIN, 2001, Pakistan: Intruding sea water threatens Indus river, UN Office for the Co-ordination of Humanitarian
Affairs Integrated Regional Information Networks article: December 31 2001
[7] IUCN, 2005, Indus Delta: A vanishing ecosystem
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