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The world's major rivers, i.e. those whose average long-term runoff volume exceeds 100km³

runoff is lost as evaporation in the flood plain and lowland parts of the basin. The Ganges and Indus in Asia, the Niger and Zambezi in Africa, the Mississippi and Colorado in North America, are all examples of such river basins. Taking all the exorheic regions as a whole, about 1100 km³ of runoff per year are lost as evaporation and does not reach the river mouth.

Thus, the total river water inflow to the World Ocean will be somewhat less than the value of renewable water resources of all the Earth's continents. Approximately half the total river water inflow to the World Ocean enters the Atlantic Ocean where four of the six largest rivers of the world go, the Amazon, the Congo, the Orinoco, and the Parana.

The smallest amount of river water - some 43000 km3 per year - flows into the Arctic Ocean but river waters are nevertheless of the utmost importance for the regime of this ocean. There is a very simple explanation for this: the Arctic Ocean contains 1.2% of the total water storage in the World Ocean while at the same time it accepts 11% of global river runoff.

To simulate the dynamic processes in the oceans, it is very important to take into account not only the volume of river water inflow but also its distribution since river runoff enters the World Ocean very unevenly. On average, about 40% of total river runoff enters the ocean in the equatorial region between 10^o N and 10^oS.