About the data
The data on freshwater resources are based on
to variations in collection and estimation methods.
• Internal renewable freshwater resources are
estimates of runoff into rivers and recharge of
In addition, inflows and outflows are estimated at
the average annual flows of rivers and groundwater
groundwater. These estimates are based on differ-
different times and at different levels of quality and
from rainfall in the country. Natural incoming flows
ent sources and refer to different years, so cross-
precision, requiring caution in interpreting the data,
originating outside a country’s borders are excluded.
country comparisons should be made with caution.
particularly for water-short countries, notably in the
Overlapping water resources between surface run-
Because the data are collected intermittently, they
Middle East and North Africa.
off and groundwater recharge are also deducted.
may hide significant variations in total renewable
Water productivity is an indication only of the
• Renewable internal freshwater resources per
water resources from year to year. The data also
efficiency by which each country uses its water
capita are calculated using the World Bank’s popu-
fail to distinguish between seasonal and geographic
resources. Given the different economic structure
lation estimates (see table 2.1). • Annual freshwater
variations in water availability within countries. Data
of each country, these indicators should be used
withdrawals are total water withdrawals, not count-
for small countries and countries in arid and semiarid
carefully, taking into account the countries’ sectoral
ing evaporation losses from storage basins. With-
zones are less reliable than those for larger countries
activities and natural resource endowments.
drawals also include water from desalination plants
The data on access to an improved water source
in countries where they are a significant source. With-
Caution should also be used in comparing data
measure the percentage of the population with ready
drawals can exceed 100 percent of total renewable
on annual freshwater withdrawals, which are subject
access to water for domestic purposes. The data
resources where extraction from nonrenewable aqui-
are based on surveys and estimates provided by
fers or desalination plants is considerable or where
governments to the Joint Monitoring Programme of
water reuse is significant. Withdrawals for agriculture
the World Health Organization (WHO) and the United
and industry are total withdrawals for irrigation and
Nations Children’s Fund (UNICEF). The coverage
livestock production and for direct industrial use
rates are based on information from service users
(including for cooling thermoelectric plants). With-
on actual household use rather than on information
drawals for domestic uses include drinking water,
from service providers, which may include nonfunc-
municipal use or supply, and use for public services,
tioning systems. Access to drinking water from an
commercial establishments, and homes. • Water
improved source does not ensure that the water
productivity is calculated as GDP in constant prices
is safe or adequate, as these characteristics are
divided by annual total water withdrawal. • Access
not tested at the time of survey. While information
to an improved water source is the percentage of the
on access to an improved water source is widely
population with reasonable access to an adequate
used, it is extremely subjective, and such terms as
amount of water from an improved source, such as
safe, improved, adequate, and reasonable may have
piped water into a dwelling, plot, or yard; public tap
different meaning in different countries despite offi-
or standpipe; tubewell or borehole; protected dug
cial WHO definitions (see Definitions). Even in high-
well or spring; and rainwater collection. Unimproved
income countries treated water may not always be
sources include unprotected dug wells or springs,
safe to drink. Access to an improved water source is
carts with small tank or drum, bottled water, and
equated with connection to a supply system; it does
tanker trucks. Reasonable access is defined as the
not take into account variations in the quality and
availability of at least 20 liters a person a day from
cost (broadly defined) of the service.
a source within 1 kilometer of the dwelling.
and countries with greater rainfall.
Agriculture is still the largest user of water, accounting for some 70 3.5a percent of global withdrawals . . . Percent 100
0 Low income
Lower middle income
Upper middle income
Source: Table 3.5.
. . . and approaching 90 percent in some developing regions Percent 100
Data sources Data on freshwater resources and withdrawals
are from the Food and Agriculture Organization of the United Nations AQUASTAT data. The GDP
estimates used to calculate water productivity are from the World Bank national accounts data-
0 East Europe Latin Middle Asia & America East & & Central & North Pacific Asia Caribbean Africa
Source: Table 3.5.
South SubAsia Saharan Africa
base. Data on access to water are from WHO and UNICEF’s Progress on sanitation and drinking water (2010).
2011 World Development Indicators
Published on Apr 4, 2011
Published on Apr 4, 2011
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