The Amazon River has the greatest water discharge of any river flowing through the Amazon Rainforest.
The river carries more water to the ocean than any other river system. Its enormous flow comes from a vast drainage basin extending across much of northern South America, including rainfall-heavy areas and snowmelt-fed headwaters in the Andes.
The Amazon begins in the Andes and travels generally eastward across Peru and Brazil before entering the Atlantic Ocean. Major tributaries include the Rio Negro, Madeira, Tapajós, and Xingu. The river’s mouth is so wide that ocean tides affect water levels far inland.
People sometimes confuse the Amazon’s discharge record with the disputed question of which river is longest. Length estimates vary depending on which headwater is counted, but the Amazon’s water-volume record is firmly established. Its floodplain, forests, and tributaries support a huge freshwater ecosystem.