Integrated Monitoring Guide for SDG 6
Step-by-step monitoring methodology for indicator 6.4.2 on water stress
Version 19 January 2017 10
5. BACKGROUND PROPO SE D INDIC ATO R AND METHO DOLOGY
This indicator derives from the indicator 7.5 on water stress that was applied during the MDG process,
defined as “Proportion of total water resources used, percentage”. It has been selected in order to
ensure continuity with that process, and for its intrinsic importance for the assessment of the water
resources of a country.
The Food and Agriculture Organization of the United Nations (FAO) has been responsible for compiling
data and calculating this indicator at the international level during the MDG period. This is done
through its Global Water Information System (AQUASTAT) country surveys since 1994. These surveys
are carried out every ten years, on average.
AQUASTAT data are obtained through detailed questionnaires filled in by national experts and
consultants who collect information from the different institutions and ministries having water-
related issues in their mandate. In order to complement the data collection and to inform the quality
control and assessment process, literature and information at the country and sub-country and river
basin level are reviewed including national policies and strategies; water resources and irrigation
master plans; national reports, yearbooks and statistics; reports from projects; international surveys;
results and publications from national and international research centres; and the Internet.
Data obtained from national sources are systematically reviewed to ensure consistency in definitions
and consistency in data from countries located in the same river basin. A methodology has been
developed by AQUASTAT and rules established to compute the different elements of national water
balances. Guidance can be found at:
http://www.fao.org/nr/water/aquastat/sets/index.stm
Estimates are based on country information, complemented, when necessary, with expert calculations
based on unit water use figures by sector, and with available global datasets. In the case of conflicting
sources of information, the difficulty lies in selecting the most reliable one. In some cases, water
resources figures vary considerably from one source to another. There are various reasons for such
differences, including differing computation methods, definitions or reference periods, double
counting of surface water and groundwater or of transboundary river flows. Moreover, estimates of
long-term average annual values can change due to the availability of better data from improvements
in knowledge, methods or measurement networks.
Where several sources result in divergent or contradictory information, preference is given to
information collected at the national or sub-national level rather than at regional or world levels.
Moreover, except in the case of evident errors, official sources are privileged. As regards shared water
resources, the comparison of information between countries makes it possible to verify and complete
data concerning the flows of transboundary rivers and to ensure data coherence at the river basin
level. In spite of these precautions, the accuracy, reliability and frequency with which information is
collected vary considerably by region, country and category of information. Information is completed
using models and/or remote sensing (for example to estimate irrigation areas for the calculation of
agricultural water withdrawal) when necessary.
Regional and global level aggregations are obtained by applying the same procedure as for country
level computation.