Most Freshwater resources data were provided by AQUASTAT, a global database of water statistics maintained by the Food and Agriculture Organization of the United Nations (FAO).
AQUASTAT collects its information from a number of sources--
- national water resources and irrigation master plans;
- national yearbooks, statistics and reports;
- FAO reports and project documents;
- international surveys; and,
- results from surveys done by national or international research centers.
In most cases, a critical analysis of the information was necessary to ensure consistency among the different data collected for a given country.