WATER%20SCARCITY%20MANAGEMENT

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WATER SCARCITY MANAGEMENT

• by Özden BILEN

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1. WHAT IS WATER SCARCITY ? Some conceptual
issues

• Scarcity Excess of demand over usable water or
  available water in a given region
• Water Availability Annual average flow per head
  of population (Standard Hydrological Index,
  SHI)
• OR
• The number of people dependent on given
  amount of water (e.g. 1000 m3/caput one
  million people reliant of one billion m3)
• Some problems defining and quantifying SHI
• (i)
• e.g SHI(1) 185 km3/67.3 million 2700
  m3/caput
• SHI(2) 95 km3/67.3 million 1400
  m3/caput
• (ii) SHI does not include underground water
• (iii) SHI masks extreme local variabilities

or
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(iv) Scarcity is partly a social and economic
construct and it is difficult to capture in a
single quantitative index

• Water scarcity is influenced by social,
  institutional, policy factors, lifestyle, water
  quality etc.
• Social economic problems might feed back to
  water scarcity problems,
• A country having better social adaptive capacity
  may be better off than a similar water scarce
  country as measured by SHI.
• Ohlson suggests that an index for Social Water
  Scarcity, SWS could be constructed through
  dividing SHI by the Human Development Index (HDI)
  (according to the UNDPs human development report
  ,1997, HDI changes in between 0.176 - 0.960)

• SHI for water availability has some a.m.
  drawbacks. However, because of its virtue of
• simplicity, it is being used as an early
  warning indicator. Yet a resource analysist
• should be aware all these points for assessing
  and interpretation of water scarcity issues.
  

• In order to make comparison among countries or
  regions using SHI, attempts have been made to
  define a threshold under which a country may be
  considered in a situation of water shortage. The
  limit of 1000 cubic meters per person is often
  quoted as representing a condition of severe
  water shortage

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2. THE WORLD FRESH WATER SUPPLY/ WATER USES AND
TRENDS

• SUPPLY
• Hydrological cycle
• Supply by rain on land 110 000 km3
• Evaporation and transpiration - 70 000 km3
• Net effect of hydrological cycle 40 000 km3
• Much of 40 000 km3 flows into the sea as floods,
  since flow rate is too large to capture, it is
  held in soil and swamps, etc.
• Excluding flood flows, baseflow(stable-runoff) is
  about 9 000-14 000 km3.
• Uneven global distribution is striking. E.g. the
  Amazon River accounts for 20 of global average
  and the Zaire River basin accounts for 30 of
  Africas total runoff.
• TABLE 1 shows global water distribution by region
  and per capita

1 km3 1 billion(milyard) m3
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• In MENA countries Yemen 176 m3, West Bank
  Gazza 105 m3, Jordan 213 m3, Israel 375 m3 per
  capita
• Chinas situation is particularly important,
  since that country with approximately one-quarter
  of the Worlds population can claim only 8 of
  its freshwater resources .
• In Africa, Kenya, Somalia, Rwanda, Etophia and
  some Sub-Saharan countries are water scarce.
  Other
• countries with pronounced rainfall variability
  include Turkey, Pakistan, India (Western and
  Southern India),
• parts of Mexico.
• Global averages only tell us that this is a
  widely shared problem, there are
• huge local and temporal variations.

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Water Use / Trends

• Figure 1 indicates that global annual
  abstractions of water out of natural system of
  rivers and lakes was about 1360 km³/year in 1950
  and will be estimated as about 5000 km³/year in
  2000 (Abernethy, 1996). In other words, global
  water abstractions during the period 1950-2000
  increased by more than three- fold. In 1950 we
  were abstracting some 10-15 percent of the
  abstractable total now we take perhaps 35-50 ,
  and if present rate of increase continue we can
  expect to reach the ceiling (in terms of global
  averages) in some 30-50 years from now.

• Currently 70 of the Worlds cultivated land is
  watered exclusively by rainfall and half of
  Worlds food comes from rainfed agriculture.
  However, Figure 1 does not include agricultural
  uses under rainfed conditions.

• Source Abernety (1996, quoted from Meybeck,
  Chapman and Helmer)
• Figure 1 Annual global abstraction of water from
  the
• natural system for human use

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http//www.unesco.org/science/waterday2000/water_u
se_in_the_world.htm
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• According to the Figure 2, agricultures share
  in overall global consumption was 85 percent in
  1950 and dropped to an estimated 68 percent in
  2000 (as global averages). During the same period
  industrial consumption had grown to 25 percent,
  while consumption by cities increased from 2
  percent to nearly 9 percent.

• The 21st century will be characterized by
  increased urbanization. By 2025, 60 of the
  World population more than 5 billion people will
  be living in cities. Many countries will be
  unable to fund both economic growth and adequate
  social and physical infrastructure for
  uncontrolled influx of people to the cities. Some
  90 of waste water generated in the large urban
  centers is discharged without any treatment
  (Butt, 1997).

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• Table 2 says that the big users are not the
  developing countries but the richer industrial
  countries of the temperate zones. On average,
  Africans only about a quarter of what North
  Americans use for agricultural purposes, and 3
  of which North Americans use for other purposes.
  Even in Asia, where about 70 of worlds
  irrigated land is, quite moderate amounts of
  water for agriculture is being used.

• Although water is abundant in Africa, poverty has
  a tremendous impact on African water resources.
  Africa has not developed irrigation to the same
  extent as other developing areas, particularly in
  Asia. For example, India, which has only about
  one-tenth the surface of Africa, irrigates five
  times as much land (Kandiah, 1988).

• Table 3 suggests that as countries become richer,
  their consumption of water for agriculture
  increase relatively little, but non agriculture
  uses grow enormously.

• Water use patterns differ between industrialized
  and developing countries. In the industrial
  countries, industrial-uses account for about 50
  , while in developing countries industries use
  no more than 20 .

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SUFFICIENT WATER RESOURCES LOW POPULATION
DENSITY
?
WATER SCARCITY
In some cases, there is no relation between per
capita water availability and consumption
This analysis shows us that water can be scarce
in different ways. There are two major sources of
scarcity with different implications

• Water Scarcity due to Low Utilization
• Water Scarcity due to High Population Density
  and/or Aridity

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3. CAUSES OF WATER SCARCITY

• Growth in population
• Environmental degradation
• Modification in land use pattern
• Global climatic change
• Pollution of water resources
• Financial and institutional problems

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Growth in Population

• The United Nations publishes high, medium and low
  population projections.
• Most people would agree that high projection can
  be ignored,
• According to medium projection 7.8 billion in
  2025 continue to grow indefinitely,
• According to low projection 7.3 billion in 2025
  cease to grow around 2040 at a level of 7.5
  billion people
• Doubling time of World population is about four
  decades with compound rate of 1.7 per year (USA
  114 years, Egypt 31 years, India 37 years, Iran
  24 years, Iraq 19 years, China 66 years, Mexico
  32 years (Butts, 1997), Turkey 44 years with
  compound rate of 1.6 per year)
• Classical Malthusian Discourse vs. Virtual Water
  Discourse
• Demographic Race between Countries

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Environmental Degradation

• Modification in Land Use Pattern
• Land use pattern may reduce the amount of surface
  water
• People are forced to use marginal lands
• Forests are cleared so that land can be used as
  agricultural purposes
• Reduction in dams storage capacity
• Poverty feeds back to environmental problems
• Global Climatic Change
• Permanent increase of CO2
• Target values for greenhouse emissions reduction
  below 1990 levels by 2012 (the EU 8, the USA 7,
  Japan 6 etc.)

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• CO2 emission by region and per capita is shown in
  Figure 3

• Poor countries argue that they can not afford to
  put the brakes on their own domestic
  industrialization
• Global warming may be irreversible
• Policy approaches for adopting or mitigating
  to global warming

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Pollution of Water Resources

• Water scarcity is not only a problem of the
  amount of water availability but increasingly as
  well a problem of water quality
• 1.2 billion people do not have access to safe
  drinking water and 2.9 billion lack to adequate
  sanitation facility

Source World Water Vision (1999) Figure 4
Number of People without Safe Drinking Water
Source World Water Vision (1999) Figure 5
Number of People without Adequate Sanita
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4. WATER SCARCITY MANAGEMENT

• To manage water scarcity, solutions could be
  divided into two broad categories
• Supply-side Measures
• Demand-side Measures

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Supply-side Measures

• Renewable freshwater resources is to be utilized
  to the limits of sustainable yields by dams,
  wells for groundwater exploitation, inter-basin
  water transfers, etc.

• 37 000 large dams were constructed in 20th
  Century, irrigated area increased from 74
  million hectares in 1950 to 274 million
  hectares at the end of 20th century.

• In some water scarce regions, e.g. ME, seawater
  desalination, sewage reclamation seems
  environmentally economic solutions.

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Only physical facilities failed to respond the
needs of growing population. And these measures
should be complemented with Demand-side Measures
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Demand-side Measures

• More efficient use of existing supplies.
• Dublin Principles of 1992 Water has an
  economic value in all its competing uses and
  should be recognized as an economic good.
• Water pricing is an important element for
  sectoral allocation of water.

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5. RECOMMENDATIONS

• Many countries confront the prospect of emerging
  water scarcity in the long term and for some that
  spectre is already on them because of decrease in
  the supply of water resource, increase in demand
  or unequal resource distribution.
• It is therefore recommended to define and
  implement a comprehensive and integrated
  framework for decision-making on water scarcity
  management. Among the multitude of decisions to
  be taken, two critical phases have been
  identified
• Phase 1 Water Resources and Demand Assessment
• - Development of key indicators,
• - Dynamic character of sectoral water demand,
• - Forecasting complemented by backcasting.
• Phase 2 Comprehensive Options Assessment
• - Focus on the methodology to be developed so
  that one can study on alternative choices in
  terms of prediction and management of
  increasingly scarce water resources,
• - Improving quality of decisions through
  Decision Support System,
• - Water politics are shifting from projects to
  policies and institutional development,
• - As a key element, institutional capacity
  building,
• - Assessing institutional capacity for
  implementation of selected options.