The document discusses floodplain management in Pakistan and provides options for diverting flood waters from heavily impacted areas to Ramsar sites. It summarizes that the 2010 Pakistan floods caused the greatest damage despite having a similar extent to prior major floods. It then analyzes three Ramsar sites in Sindh - the Indus Dolphin Reserve, Drigh Lake, and Deh Akro-II Desert Wetland Complex - and determines that Deh Akro-II would be the best option for diverting flood waters since it is located near severely impacted districts but away from major settlements and could help restore the wildlife sanctuary. Satellite imagery was used to map the 2010 flood extent and land use in the region.

1. FLOODPLAIN MANAGMENT
Preliminary report on Indus River System and Ramsar Sites Restoration
Hassaan Ahmed
Ali Shah Jatala
8/7/2015

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I. INTRODUCTION
FLOODS is overflow of a large amount of water
beyond its normal limits, especially over what
is normally dry land is known as flood. It can
may cause much destruction. There are
different types of floods depending upon their
intensity. Flooding is a longer term event than
flash flooding: it may last days or weeks.
FLASH FLOODS caused by heavy or excessive
rainfall in a short period of time, generally less
than 6 hours. Flash floods are usually
characterized by raging torrents after heavy
rains that rip through river beds, urban streets,
or mountain canyons sweeping everything
before them. They can occur within minutes or
a few hours of excessive rainfall. They can also
occur even if no rain has fallen, for instance
after a levee or dam has failed, or after a
sudden release of water by a debris or ice jam.
Floods are among the most recurring and
devastating natural hazards, impacting human
lives and causing severe economic damage
throughout the world. It is understood that
flood risks will not subside in the future, and
with the onset of climate change, flood
intensity and frequency will threaten many
regions of the world [1], [2].
Flooding occurs most commonly from heavy
rainfall when natural watercourses do not
have the capacity to convey excess water.
However, floods are not always caused by
heavy rainfall. They can result from other
phenomena. Dam failure, triggered for
example by an earthquake, will result in
flooding of the downstream area, even in dry
weather conditions.
Other factors which may contribute to flooding
include:
 volume, spatial distribution, intensity
and duration of rainfall over a
catchment
 the capacity of the watercourse or
stream network to convey runoff
 catchment and weather conditions
prior to a rainfall event
 ground cover
 topography
FLOOD PLAINS are the low, flat, periodically
flooded lands adjacent to rivers, lakes and
oceans and subject to geomorphic (land-
shaping) and hydrologic (water flow)
processes. As distinguished from the
floodplain, a river' floodway is the dry zone
typically between levees, which is designed to
convey flood waters (making wonderful areas
for bike trails and parkways because it is only
periodically flooded).
Unfortunately, a river's floodplain has been
viewed as completely separate from a river's
active channel. The river and its floodway are
usually the focus of construction and control,
while fertile, flat and "reclaimed" floodplain
lands are usually the focal points for other
activities such as agriculture, commerce and
residential development.
It is only during and after major flood events
that the connections between a river, its
floodway and its floodplain become more
apparent. These areas form a complex physical
and biological system that not only supports a
variety of natural resources but also provides
natural flood and erosion control. In addition,
the floodplain represents a natural filtering
system, with water percolating back into the
ground and replenishing groundwater.
A floodplain is a flat or nearly flat area of land
adjacent to a river or stream which floods
when the water level rises during times of high
discharge, such as after heavy rains.

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Floodplains provide a range of valuable
ecosystem services, especially in flood risk
reduction by helping to store the excess
floodwater and to slowly release it back into
the river system and into the groundwater
aquifers. This has the effect of reducing the
peak height and speed of the flood discharge,
so reducing the damage that may be caused
downstream. Floodplains also act as spawning
and rearing ground for many river fish species
during the times of flood and as the high water
recedes. Flood waters also bring nutrient rich
sediment which covers the flooded ground,
making it particularly fertile for agriculture
after the waters recede.
FLOODPLAIN MANAGEMENT is the operation
of a community program of preventive and
corrective measures to reduce the risk of
current and future flooding, resulting in a more
resilient community. These measures take a
variety of forms, are carried out by multiple
stakeholders with a vested interest in
responsible floodplain management and
generally include requirements for zoning,
subdivision or building, building codes and
special-purpose floodplain ordinances.
Mitigation practices, such as flood proofing or
retrofitting a flood prone building, are equally
beneficial to reducing flood damages to the
community. Mitigation is the cornerstone of
emergency management. It is the ongoing
efforts to lessen the impact disasters have on
people and property. Mitigation involves
keeping homes away from floodplains,
engineering bridges to withstand earthquakes,
creating and enforcing effective building codes
to protect property from hurricanes—and
more. In response to the unacceptable loss of
life and property from recent disasters, and the
prospect of even greater catastrophic loss in
the future, the National Mitigation Strategy
has been developed to provide a conceptual
framework to reduce these losses. Hazard
Mitigation involves recognizing and adaptation
to natural forces and is defined as any
sustained action taken to reduce and eliminate
long-term risk to human life and property.
Figure 1 The Indus River system in the region of Sindh,
it shows the major canal system of the region and
the three barrages (Guddu, Sukkur, Kotri)
Figure 2 Shows the floodplain of the region
highlighted with red

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II. STUDY AREA & DATA
A. Indus River Basin
The Indus River is a major river which flows
through Pakistan. It also has courses through
western Tibet in China and Northern India.
Originating in the Tibetan plateau and runs in a
course through the Ladakh region of Jammu
and Kashmir, and enter in extreme north of
Pakistan through Skardu region and flows to
merge into the Arabian Sea. The total length of
the river is 3,180 km and has a total drainage
area exceeding 1,165,000 km2. Its estimated
annual flow stands at around 207 km3, making
it the 21st largest river in the world in terms of
annual flow.
The monsoon season starting in June and
carrying on to the month of October bring
heavy rainfall with them and the region has a
long history of floods occurring during this
time. And those of 1956, 1973, 1976, and 1992
are the most noticeable in damages and
extent.
The flood of 2010 (termed as Super Flood)
though has a smaller (or about equal) extent
than the others major floods (the ones
mentioned above) caused the greatest
damage. This may have been due to the timing
of the flood, locations of the embankment
breaches, and the significant increase in
economic development that had occurred in
the floodplains by 2010.
B. Ramsar Sites
As of March 2013, there are nineteen Ramsar
sites, covering an area of 1,343,627 hectares
(3,320,170 acres) in Pakistan.
The three areas being studied in the Sindh
region are the; a) Drigh Lake one of the
wetland identified directly in the first
convection b) Indus Dolphin Reserve added in
2001 c) Deh Akro-Ii Desert Wetland Complex
added in 2002.
Drigh lake is directly sustained by the Indus
River and some local monsoon rains. The lake
has an area of 164 hectors.
The Indus Dolphin Reserve stretches a
distance of 170 km, from the Sukkur Barrage
upstream to the Guddu Barrage. The river
stretch is critical for the survival of Indus
Dolphins (some 500 in number). It has an area
of approximately 125,000 hectors.
Deh Akro-Ii Desert Wetland Complex is located
about 300 km form Karachi. It has an
approximately 36 lakes and cover an area of
20,500 hectors. This wetland has a horde of
endangered spices and declared a Wildlife
Sanctuary in 1998.
C. Satellite Remote Sensing Data for
Flood Extent Mapping
We used MODIS for flood inundation mapping.
MODIS instruments onboard NASA’s Terra and
Aqua satellites offer a unique combination of
quasi-global daily coverage with acceptable
spatial resolution. These capabilities are being
utilized for flood monitoring at regional and
global scales. Brakenridge et al. [3], [4]
demonstrated that MODIS data can be used to
distinguish between flooded and nonflooded
areas with suitable spatial resolution. This can
be very crucial in regions where no other
means of flood monitoring are available.
YEAR DIRECT LOSSES LOST LIVES AFFECTED VILLAGES FLOODED AREAS
1956 148 160 11,609 74,406
1973 2,388 474 9,719 41,472
1976 1,621 425 18,390 81,920
1992 1,400 1,008 13,208 38,758
2010 10,056 1,600 NA 38,600
Table 1. Information of major floods that happened in the flood plains of Indus

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Several spectral bands at spatial resolutions of
approximately 250 and 500 m are appropriate
for accurate discrimination of water from land.
D. Satellite Remote Sensing Data for
Land use Mapping
Landsat freely available data (USGS, 2013), was
used for land-cover classification. The data
scene numbers are Path 151 and 152 Row 040
to 044.
General land-cover of the area include: shrub-
land, cropland, forest, grassland, desert, other-
land, wetland, rocks and settlements. A total of
four scenes of Landsat images were used.
The images were selected within the dry
season of the area, normally most of the time
(leaving the monsoon months of July to
September).
III. METHODOLOGY
The methodology consists of 2 major steps; a)
Identifying the major flood areas and b) Land
use mapping of the study area.
A. Satellite Remote-Sensing-Based
Flood Mapping
There are several methods for identifying
flooded versus nonflooded areas using optical
remote sensing imagery. One is the Iterative
Self-Organizing Data Analysis Technique
Algorithm (ISODATA) which uses the Euclidean
distance in the feature space to assign every
pixel to a cluster through a number of
iterations.
Other very common classification is the Maxi-
mum Likelihood used in this case. To perform
maximum likelihood the user defines a training
data which would be used for by the software
which judges each pixel value to the class it will
most probably belong.
The method for flood detection and mapping
using satellite imagery included the following
steps.
1. Terra MODIS subsets covering the
region of Pakistan were retrieved
from the NASA Web site
http://rapidfire.sci.gsfc.nasa.gov/subs
ets
2. Color composite images were
downloaded for image processing. The
false-color composite of MODIS bands
1, 2, and 7 (red, near-infrared, and
SWIR) has a resolution of 250 m. The
true-color composite of MODIS bands
1, 3, and 4 was used for visual
interpretation.
3. False-color composite image were
subset to the region of interest
4. Training data was set for the whole
region. (creating multiple water
classes for muddy, clean waters)
5. All the water classes were combined
into one water class.
6. The raster-type images were exported
in Geographical Information System
(GIS)-compatible format for further
processing.
B. Satellite Remote-Sensing-Based
Land use Mapping
The method for the classification of land use
using the Landsat images was:
1. Landsat 8 bands 2, 3, 4, 5 and 7 stacked
in different combinations.
2. The images of the same date were
mosaicked together but not of
different dates so as to maintain
spectral coherency between scenes.
3. Image interpretation was done to
identify classes of interest. The major
classes were shrub land, cropland,
forest, grassland, desert, other-land,
rocks and settlements.
4. Training sites of the chosen classes
were selected using expert knowledge
with aid of Google Earth GeoEye
images.
5. Maximum likelihood classifier was
used again to classify the whole
region.

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IV. RESULTS
A. Flood Extent Mapping
B. Land Use Mapping
Figure 3 Flood Extent Mapping of Pakistan Floods 2010 using the MODIS Imagery
Figure 4 Land Use Mapping of Sindh Province using Landsat 8 Dataset

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C. Ramsar Sites:
i. Indus Dolphin Reserve
Indus dolphin reserve is
located near the Indus
River and is near one of
the most affected (in
terms of area) district
(Shikarpur, Jaccobabad,
Kashmore). There are no
major settlements near
this point and can be used
to flush the flood water
here. But it might not help
the flooding in the districts
adjacent in a proper
manner but can be
affective in lower areas of
Sindh.
ii. Drigh Lake
Drigh Lake is located
around a number of small
and a very large
settlement (Larkana City).
The act of moving flood
water to this location can
be quite risky according to
the report. And can be
quite dangerous without
proper planning and
knowledge.

8. iii. Deh Akro-II Desert Wetland Complex
Deh Akro-II Desert Wetland Complex can be
considered one of the prime locations to divert
the water flow as it not only lies near the
desert and two of the most severely hit
districts (Dadu and Jamshoro) but not many
major settlements are near the site.
The flood waters that hit the two districts can
be diverted here to restore the waters of this
wetland complex which is not only a ramsar
site but also a wildlife sanctuary. But it has to
be made sure that water that cannot be
sustained (more than that can be sustained by
the by this sanctuary) should not be diverted
here.

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References:
1. S. N. Jonkman "Global perspectives on loss
of human life caused by floods"
Nat. Hazards, vol. 34, no. 2, pp. 151-175, 2005
2. J. McCarthy Climate Change 2001: Impacts,
Adaptation, and Vulnerability: Contribution of
Working Group II to the Third Assessment
Report of the Intergovernmental Panel on
Climate Change
2001, Cambridge Univ. Press
3. Brakenridge, E.Anderson, S.Nghiem,
S.Caquard, and T.B.Shabaneh, “Flood
warnings, flood disaster assessments, and
flood hazard reduction: The roles of orbital
remote sensing,”
Proc. 30th Int. RSE, Honolulu, HI, Nov., 2003.
4. L. C. Smith, “Satellite remote sensing of
river inundation area, stage, and discharge: A
review,”
Hydrol. Process., vol. 11, no. 10, 1997.