According to World Bank, ″renewable internal freshwater resources flows refer to internal renewable resources (internal river flows and groundwater from rainfall) in the country.″[4]
According to Food and Agriculture Organization, ″internal renewable water resources (IRWR) represents long-term average annual flow of rivers and recharge of aquifers generated from endogenous precipitation. External renewable water resources (ERWR) represents that part of the country's long-term average annual renewable water resources which are not generated in the country. It includes inflows from upstream countries (groundwater and surface water), and part of the water of border lakes and/or rivers. Total actual renewable water resources (TARWR) is the sum of internal renewable water resources and incoming flow originating outside the country. The computation of TARWR takes into account upstream abstraction and quantity of flows reserved to upstream and downstream countries through formal or informal agreements or treaties. It is a measure of the maximum theoretical amount of water actually available for the country.″[5]
Out of all the water on Earth, saline water in oceans, seas and saline groundwater make up about 97% of it. Only 2.5–2.75% is fresh water, including 1.75–2% frozen in glaciers, ice and snow, 0.5–0.75% as fresh groundwater and soil moisture, and less than 0.01% of it as surface water in lakes, swamps and rivers. Freshwater lakes contain about 87% of this fresh surface water, including 29% in the African Great Lakes, 22% in Lake Baikal in Russia, 21% in the North American Great Lakes, and 14% in other lakes. Swamps have most of the balance with only a small amount in rivers, most notably the Amazon River. The atmosphere contains 0.04% water. In areas with no fresh water on the ground surface, fresh water derived from precipitation may, because of its lower density, overlie saline ground water in lenses or layers. Most of the world's fresh water is frozen in ice sheets. Many areas suffer from lack of distribution of fresh water, such as deserts.[6][7]
List of countries by total renewable water resources
The following table provides information on annual renewable water resources based on data published by World Bank[8][9] and Food and Agriculture Organization.[2] Total renewable water resources per capita are calculated using the World Bank's population estimates. Sorting is alphabetical by country code, according to ISO 3166-1 alpha-3.
Country/Territory/Region/Group
Internal renewable water resources (bln m3/year)
External renewable water resources (bln m3/year)
Total renewable water resources (bln m3/year)
Total renewable water resources per capita (m3/inhab/year)
Freshwater withdrawal as % of total renewable water resources (%)
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