Amazon River

The Amazon hand basin, the largest drainage basin in the world, covers an area of some 6,915,000 square kilometres (2,670,000 sq mi), or some 40 percent of South America. It gathers its waters from 5 degrees north freedom to 20 degrees south freedom. Its most remote sources are found on the inter-Andean upland, just a short distance from the Pacific Ocean.

The area covered by the water of the River and its tributaries more than triples over the course of a year. In an average dry season 110,000 square kilometres (42,000 sq mi) of land are water-covered, while in the wet season the flooded area of the Amazon Basin rises to 350,000 square kilometres (135,000 sq mi). At its widest point the Amazon River can be 11 kilometres (7 mi) wide during the dry season, but during the rainy season when the Amazon floods the surrounding plains it can be up to 45 kilometres (28 mi) wide.

The quantity of fresh water released by the Amazon to the Atlantic Ocean is mammoth: up to 300,000 m³ per second in the showery season. The Amazon is liable for a fifth of the total volume of fresh water entering the oceans global. Offshore of the mouth of the Amazon, potable water can be drawn from the ocean while still out of sight of the coast, and the salinity of the ocean is notably lower a hundred miles out to sea.