Remote Sensing and Geographic Information Systems for Design and Operation of Water Resources
Systems (Proceedings of Rabat Symposium S3, April 1997). IAHS Publ. no. 242, 1997
23
Potential applications of satellite remote sensing
(SRS) and GIS in maximizing the use of water
resources in the Middle East: examining Iraq
as a case study
SERWAN M. J. BABAN
GRRU Group, Geography, School of Natural and Environmental Sciences,
Coventry University, Priory Street, Coventry CV1 5FB, UK
Abstract The countries of the Middle East region are currently experiencing
an increase in water demand. Consequently, water resource managers and
decision makers will be required to take measures to cope with extreme
conditions and the variability in both, supply and demand. These decision
makers will need to use every aid available in order to identify management
options for optimizing the use of these limited water resources. The
applicability of satellite remote sensing (SRS) within a geographic
information system (GIS) as a water management tool, focusing on Iraq as a
case study, has been examined. The relevance and the possible success of a
range of applications is presented. Based on the outcome of these
assessments a hydrological GIS appraisal and management system is
proposed. This management system will use SRS as an information source
and a GIS as an analytical tool. This will enable decision makers to
extrapolate, predict, update, plan, evaluate, compare, simulate and visualize
various management actions. It will help to anticipate the consequences of
implementing each action over different periods of time in an objective
manner, ultimately enabling them to optimize management decisions.
INTRODUCTION
In the Middle East water resources are limited, and are currently decreasing, whilst
the demand for water consumption is increasing for reasons such as the expanding
industrialization and population growth. This combination makes the distribution of
this limited resource very difficult and potentially explosive. A recent investigation
by the Center for Strategic and International Studies (Washington, DC), concluded
that the situation is likely to become so acute that, in the near future, water will be
the dominant resource of the Middle East (Star & Stoll, 1988). This prediction is
most likely to be realized for three major reasons: First, for geopolitical reasons,
since water resources are not restricted by international boundaries. An examination
of the recent history of the region indicates that the race to develop water resources
has already started. Many upstream countries in the Middle East have drawn up
plans to divert shared river and aquifer water supplies to fill reservoirs and irrigation
systems in order to increase their agricultural production. Syria is planning to divert
water from the Yarmuk River, Turkey from the upper Euphrates and Tigris, Libya
from its shared aquifer and Ethiopia from the Blue Nile (Clark, 1991). Secondly,
natural problems hinder the fall use of the available water resources in the region.
24
Serwan M. J. Baban
Most of the lakes and reservoirs in the Maghreb States of North Africa suffer from
sedimentation problems. Consequently the increase in water demand over time will
be associated with a diminished storage capacity. The third problem is the
weaknesses of the decision-makers. Some managers may have a poor general
knowledge of the problem due to their appointment for political reasons (Perera &
Tateishi, 1995). In order to actively promote political and social stability, minimize
the damage and strike a balance between environmental and economic concerns,
water managers and decision makers should use every aid available as they attempt to
mange their limited water resources.
THE USE OF SRS AND GIS-TECHNIQUES
Remote sensing and GIS might be able to contribute effectively towards the
objectives identified above. SRS has many advantages, including accessibility,
synoptic viewing, uniformity of collected information, repetitive coverage and cost
effectiveness. These advantages will provide an opportunity to adopt an holistic
approach, enabling water resources to be studied as an integrated system rather than
individual entities. The holistic approach, using a GIS, will allow managers to
observe, study and monitor the effects and consequences of a particular decision on
water resources within a large geographical area concurrently and over appropriate
periods of time. It will also provide data for areas where no ground measurements
are available, based on the interpolation of area-based information from sampled sites
with similar attributes; subjected only to the size of the area and the spatial resolution
of the imagery.
The potential of SRS is sometimes difficult to realize. This is because the current
civilian satellites do not provide data with the necessary spatial and temporal
resolution for some applications, as well as suffering from cloud cover (Barrett &
Curtis, 1992). The spatial and temporal resolution of satellite data, however, is
suited to all applications discussed in this paper. SRS has been successfully employed
in various relevant applications which can be broadly grouped into surface and
subsurface applications: (a) Applications concerning surface water, are based on the
fact that the water absorption is less than 10% of the incoming electromagnetic
radiant energy in the visible wavelength (0.4-0.6 urn), while it will increase rapidly
above this limit to reach about 60% at 0.7 urn. Sensor bands are designed to benefit
from these characteristics. Sensors operating in the band 0.6-0.7 um show good
contrast between land features and vegetated/non-vegetated areas (Curran, 1985),
while sensors operating in the 0.8-1.1 urn band are best suited to reveal most contrast
between land and water features, (b) Applications in subsurface water mapping
include both groundwater and soil moisture. Groundwater is mapped indirectly. This
is done by mapping a significant number of groundwater-related phenomena such as
detecting fractures, and the intersection of linear fractures or lineaments, which
correlate with the occurrence of groundwater or, by locating anomalous areas of
temperature in streams or coastal regions, which might be due to groundwater
outflow (Askew & Nemec, 1980; Siegal & Gillespie, 1980). Soil moisture is also an
important water resource as it is the immediate water supply for crops. The presence
of soil moisture affects the characteristics of the electromagnetic radiation reflected
Satellite remote sensing and GIS for maximizing water resources in Iraq
25
or emitted from soil due to the basic effect that moisture has on reflectance. This
field is well established and applications include estimating soil water content (Ideso
et al, 1975; Ideso & Ehrler, 1976) and evaluating soil moisture (Schmer & Werner,
1974; Barrett & Curtis, 1992).
This paper seeks to illustrate the potential and pitfalls of employing SRS and GIS
in maximizing the use of water resources in the Middle East. Iraq has been selected
as a case study in order to demonstrate the relevance and applicability of each
potential application. Based on the success of these applications a Drainage Basin
Information System is proposed to store, integrate, manage and analyse data relating
to water resources. Iraq was chosen for three reasons. First, it is one of the most
northerly Arab countries and will represent the worst possible scenario for cloud
cover throughout the year. Secondly, the water shortages have parallels in almost
every other country in the region. Thirdly it is likely to be faced with a unique water
shortage scenario in the future and SRS and GIS might help to minimize the potential
hazards and possible damage.
POTENTIAL APPLICATIONS OF SRS IN IRAQ
SRS holds great potential for a range of applications in a country like Iraq which has
little or no cloud cover during summer (June-September). Agricultural systems are
simple, pollution is limited and regular ground referenced data can be gathered from
the establishments which are in charge of rivers, dams and reservoirs, irrigation and
reclamation schemes. These characteristics indicate the practicality of employing
satellite data to investigate and manage the use of water resources in Iraq. The main
sources of water are the Tigris and Euphrates which flow into Iraq from, Syria and
Turkey. These countries have plans using larger amounts of the river water which
consequently will reduce the flow into Iraq (Clark, 1991). In case of a reduction
crops will fail, water quality will decline due to increased salinity, groundwater
storage will be reduced and, overall, a variety of water-related hazards will occur.
As a result water is likely to become an even more precious resource in Iraq in the
future. Consequently accurate and judicious management of limited water resources
are of great importance. The more information the water manager has about the
hydrologie cycle in the country, the better he is able to make decisions allocating the
scarce water resources for consumption, industrial use, irrigation, power generation
and recreation. In times of excess, flood control may become the primary task; in
times of shortage, irrigation and power generation may be primary concerns. One
way of achieving this is by adopting an holistic view by establishing a GIS for which
Landsat images could provide a regular update. Such an Information System could
then be employed for operational purposes; an arrangement which may perusade
managers that SRS in combination with a GIS holds a great potential. These potential
applications include:
(a) Landcover and landuse. Landcover and landuse are important for hydrological
studies, first, because they determine to a large extent the process of runoff
generation. Secondly, they are excellent indirect indicators of the hydrologie
conditions and the geophysical characteristics which determine them. Information
on landcover and landuse is also of indirect, but fundamental, importance to the
26
(b)
(c)
(d)
(e)
Serwan M. J. Baban
estimation of current and future demands for water. In Iraq the principle use of
water is for irrigation. It is very difficult, by conventional means, to accurately
survey the areas sown each season to each type of crop, and yet without such
information it is impossible to design and operate agricultural water supply
schemes in an effective manner. This application is possible as many cloud free
coverages can be obtained.
Water supply. The majority of the applications to be discussed are concerned
with improving the understanding of the hydrology of Iraq as a basis for an
assessment of its surface and groundwater resources. Landsat observations can
be used to aid in the location of potential dam sites, aqueducts and canals and in
this way contribute directly to the planning of water resource projects designed
to meet the national water demand. This application is particularly important as
the fate of reliable continuous water sources (Tigris and Euphrates) are likely to
be subject to future reductions. More reservoirs and water storage are likely to
be needed in order to fulfil the water needs of the country.
Mapping of river networks (Tigris and Euphrates and their tributaries).
Satellite imagery can provide frequent images of the Tigris and Euphrates
configurations. Comparing multidate images can clearly indicate the vulnerable
portions of the embankments and spurs where the rivers are concentrating their
erosional attack. These information will help engineers to plan erosion control
works. This application is possible as the increase in inflow takes place in late
spring the weather conditions are suitable for obtaining many satellite images.
Mapping of floods. The Tigris and Euphrates inundate their flood plain between
April and May. Immense areas in lower Iraq are regularly flooded and levees
often collapse resulting in wide scale damage. Satellite imagery of these rivers
and their basins before, during or even few days after the flood can provide good
coverage for a vast area study (Deutsch & Ruggles, 1978). Improved contrast
between land and water boundaries can be obtained by rationing and contrast
stretching techniques. This will furnish crucial information concerning the
floods, help to appraise the spatial extent of flood-prone areas and rapidly
estimate the economic consequences of flooding, particularly with respect to
agriculture. This information can also be used for the planning of flood control
and the development of flood protection measures. The existence of cloud-free
skies, and the duration of the flood which usually extends for a week or more,
makes this application possible.
Drainage basin and river characteristics. Mapping of landforms and drainage
networks is important in delineating basin boundaries and the major physical
dimensions affecting the occurrence of a stream flow. Both automated and visual
analyses of satellite data can detect changes in the drainage pattern, land
cover/land use (forest, agriculture, barren land, settlement, wetland, waterbody)
in river basins accurately. The reconnaissance and development of water
resources in many developing countries, including Iraq, is based on simple
regression models relating streamflow to drainage basin characteristics. Near
infrared bands (0.7-1.0 urn) are reliable for preparing maps of the Tigris and
Euphrates river networks, basin boundaries, drainage basins, drainage density
(total length of channel per unit area) and stream frequency (number of junctions
per unit area). These are the most important parameters in developing regional
Satellite remote sensing and GIS for maximizing water resources in Iraq
(f)
(g)
(h)
(i)
27
(national) hydrologie models which can be involved in many calculations and
predictions concerning the development of water resources in rivers. This
application is possible as many coverages can be obtained under suitable
conditions.
Snow cover mapping. The extent of snow cover, which represents the stored
amount of water in the Zagros mountains, and the state of the snow are both
important for river flow forecasting. This information is necessary for water
power generation, irrigation, domestic water supply, flood control and planning
by water management generally. If a multiple purpose reservoir is to maintain a
specified storage capacity to leave room for flood control, and at the same time
keep a minimum water volume stored in order to improve the low flows, its
successful operation depends on short-term and seasonal forecasts of inflow. The
cloud cover might prevent a useful application during the winter. Such an
application requires scientific coordination between the neighbouring countries
Iraq and Turkey.
Mapping and monitoring surface water storage for assessing water
availability and for planing reservoir regulation and National Integrated
Water Resource Utilization. Time based information on the quantity of water
available in storage reservoirs and lakes is required for judicious utilization for
irrigation and for hydropower development. Satellite data can help estimating the
volume of storage either through mapping of depths (if possible) and extensions
of water or establishing statistically significant relationships between the water
area and the stored water volume (Baban, 1993b). The repetitive coverage will
help to estimate the water availability not only in the beginning of the
agricultural season, but also during its depletion with time so that irrigation
targets can be realistically fixed and achieved. This application will become
extremely important when the second and the subsequent phases of filling of the
Atta-turk dams will start and the water inflow into Iraq will be reduced. Water
development and irrigation project calculations should be based on the available
water storage within Iraq. Cloud cover may be the major limiting factor in
monitoring efforts during winter time and the early spring season.
Studying sedimentation problems in reservoirs. Sedimentation in reservoirs is
a serious problem with most impoundments. Sedimentation reduces their capacity
and shortens their productive life. Remote sensing techniques can map
concentrations of suspended solids/turbidity in the surface water (Baban, 1994).
This may help eliminating or tracing sediment sources, usually as a result of
bank or soil erosion. Cloud cover might be a serious limiting factor in winter
time and the early spring season, particularly in northern Iraq, where most of the
tributaries exist.
Detecting groundwater. Satellite data are useful for mapping zones of potential
groundwater resources. From satellite imagery a significant number of waterrelated phenomena can be surveyed qualitatively and, occasionally,
quantitatively. Examples include landforms, drainage patterns, structural
lineaments, geological formations of interest (mostly limestone and
conglomerates) vegetation patterns, recharge and discharge areas. This
information is of great value in large scale preliminary investigations of available
groundwater resources (thus saving time, labour and the expense of ground-
28
Serwan M. J. Baban
search procedures). This would be valuable in many parts of central and western
Iraq, where groundwater is the main source of water. Such groundwater
resources can be used to supplement the limited sources of surface water for
irrigation in most parts of the country. This application is possible as all the
necessary conditions are fulfilled for successful ground coverage during the long
dry summer season.
(j) Soil moisture. Soil moisture information is important to the agriculturist. A
deficit in moisture may lead to the wilting of plants, and timely remedial action
through irrigation can save the crops. Remote sensing has a crucial role to play
in this field by ensuring the optimum use of water and the best possible
conditions for various crops.
(k) Monitoring agricultural resources. Irrigated areas fed by reservoirs are
distinctly visible on satellite imagery. Multitemporal data sets could be used to
monitor the irrigated cropland through time. This information could be used
effectively in many applications such as the establishment of an agricultural mapping programme, which is necessary to provide information on soils, percentage
of vegetation cover and land use for delineation of new agricultural areas, is an
application where this information could be used effectively. Information on
topography would be of assistance in irrigation planning and watershed management. It can also provide a significant input to water consumption models for
large irrigation projects, and for forecasting and estimating crop production.
Determining the effectiveness of various irrigation and cropping methods,
different methods have varying levels of water application efficiency and
recommendations. Improved efficiency levels could be made particularly where
non efficient cropping patterns and irrigation methods are used. These
applications will increase in importance as water resources are reduced and better
management is needed to make higher production and optimum crop selection
with less water available. This application is possible through the summer, but
cloud cover will be the major limiting factor during the winter.
(i) Water quality. Detecting the chemical, physical and biological characteristics of
all water bodies in the country, and identifying the source of any possible
pollution or contamination which might cause degradation of the water quality, is
also possible with SRS (Baban, 1993a, 1994). This application will become more
important as the effects of eutrophication are speeded up and magnified due the
reduction in water quantity. Industrial discharges to the waterbodies will then
represent a real threat to water quality, particularly in the summer season, where
the temperature and light, the other two necessary parameters for algae growth,
are available. By using satellite imagery and remote sensing techniques all
waterbodies can be classified trophically and monitored regularly by updates.
Representative individual members for each class could be selected for ground
referenced data collection and for calibration purposes (Baban, 1996).
A PROPOSED DRAINAGE BASIN INFORMATION SYSTEM FOR IRAQ
Planning and management of water resources at national level will call increasingly
for an integrated overview of different types of hydrological data gathered from
Satellite remote sensing and GIS for maximizing water resources in Iraq
29
different sources, by variety of means, and often maintained in separate
establishments. A homogenization should be introduced by establishing
organizational devices, such as a National Office for Water Resources and Planning.
A GIS is necessary to handle and analyse the large amount of data. Fig. 1 shows a
proposed Drainage Basin Information System, which could be used to store,
integrate, manipulate, combine and analyse spatial and temporal data as well as to
visualize data from various sources. The system should also be used for constructing,
simulating and modelling various management scenarios responding to a range of
conditions for a specified problem.
Data input
(a) Ground Referenced Information. This consists of two parts: (i) "Surface
(Land) Information" such as landcover, land use, topography, geology,
structure, soil, husbandry practices, crop types, industrial locations, etc.. These
information can be used for checking and calibrating remotely sensed data, (ii)
"Hydrological Information", which can contain information on surface water,
ground water and the drainage basins (Tigris and Euphrates).
The information listed in (i) and (ii) will be stored in a digital form and the GIS
will facilitate data integration in terms of resolution, scale and projection
systems.
(b) Remotely Sensed Information. After performing all necessary corrections on
the raw data the integration process is followed by a data selection and
processing stage. Individual acquisition dates and bands could be selected and
subjected to image processing techniques in order to find the optimum starting
point for the interpreter. A image processing stage follows, where different
individual bands could be combined in different ways such as rationing in order
to create and enhance the required information.
All information is stored in a central Database. There will be a display facility in
order to visualize and monitor the effects of the applied data manipulation processes
for both data sources, the Ground Referenced Information and the Remotely Sensed
Information.
Data integration and processing
(a) Relevant layers of "Surface (Land) Information" can be selected and combined to
create specific "land units" according to the purpose of the operation/research.
(b) Relevant sections from "Hydrological Information" layers can be selected and
combined to extract specific "hydrological units" according to the purpose of the
operation/research.
(c) Different "land units" can be selectively combined with the "hydrological units"
to form a purpose-acquired ground-referenced data map.
(d) Established algorithms for different applications of interest using Remotely
Sensed Information could be used to extract, calculate/estimate, interpolate/
extrapolate and store all necessary parameters for the whole area of interest.
Senvan M. J. Baban
30
GROUND REFERENCED
INFORMATION
|HY
HYDROLOGICAL
NFORMATION
LAND
INFORMATION
REMOTELY SENSED
INFORMATION
| RAW DATA |
Processing Stage
Obtain basemaps for
Obtain basemaps for
o Geometric Correction
a Surface water
O Land cover
a Radiometric Correction
a Groundwater
O Topography
a Atmospheric Correction
a Water quality
parameters
a Drainage basins
a etc
Implement
Fig. 1 A proposed Drainage Basin Information System for managing water resources
in Iraq.
Satellite remote sensing and GIS for maximizing water resources in Iraq
31
(e) The output from analyses of Remotely Sensed Information could be compared
with values obtained from Ground Reference Information by using standard
statistical measures. A calibration stage for the remotely sensed data can follow.
Data analysis
(a) The estimated values from analyses of Remotely Sensed Information can be
compared with previous values/estimates of the same parameters. The differences
or changes between images/maps presenting their concentrations and spatial
distributions can be analysed and stored.
(b) GIS facilities can be used to interpolate/extrapolate, display and compare
between the value and distribution pattern of different output sources and to
establish variations between different parameters and update the information
about water resources in the areas of interest as well as storing this information.
(c) The GIS could be used: (i) to identify potential problems and their geographical
locations, (ii) to establish various management scenarios responding to various
conditions of the identified problem and (iii) to run these scenarios and reflect on
the resource management, environmental, economical and social consequences of
each action over various periods of time.
CONCLUSION
The examination and analysis described above indicates the suitability of SRS and
GIS for managing limited water resources in the Middle East. The following aspects
of SRS have to be suitable for applications, which are of interest for a hydrologist:
spatial resolution, spectral resolution, radiometric resolution and temporal resolution
as well as having cloud free skies. Encouraging factors for using SRS in this region
include simple systems especially agricultural systems, the limited amount of
pollution and the national ownership of water the resources.
Adopting the proposed Drainage Basin Information System will have direct and
indirect advantages: directly, it will help managers to adopt an holistic approach and
will update them with information concerning the quantity and quality of available
water resources within a particular period, and through the GIS various management
options can be examined, suggesting the best option to effectively manage these
resources to satisfy a predefined priority list. Indirectly, it will promote objective
thinking, planning and decision making.
Broadly speaking this, and other similar systems, are required by water resource
managers to conduct all of the examined application in a safe "virtual" medium
without causing irreversible damage in the real environment, in the same manner as
new pilots get introduced into flying through simulations.
Acknowledgement The author thanks Professor Ian D. L. Foster for reading and
constructively commenting on the paper.
32
Serwan M. J. Baban
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