i think about 50
Explanation:
Amaze (or bore) your friends and colleagues with some Amazon trivia. Who knows, it might even win you big bucks someday on a game show! The Amazon IS the world's greatest river. The Nile of Africa may be slightly longer, depending on how you measure each river, but for many other reasons the Amazon River is the undisputed title holder - the greatest river on the planet, in the solar system, and perhaps even in the Milky Way galaxy (at least no-one from planets orbiting Betelgeuse or Antares has yet provided convincing evidence that they have a bigger river on their planet!). Read on!
If size is important to you... The average discharge of water into the Atlantic Ocean by the Amazon is approximately 175,000 m3 per second, or between 1/5th and 1/6th of the total discharge into the oceans of all of the world's rivers! This discharge is 4-5 times that of the Congo River (the second largest in ocean discharge), and 10 times that of the Mississippi. The Rio Negro, a tributary of the Amazon, is the second largest river in the world in terms of water flow, and is 100 meters (over 300 feet) deep and 14 kilometers (~9 miles) wide near its mouth at Manaus, Brazil.
Raindrops keep falling on my head! Average rainfall across the whole Amazon basin is approximately 2300 mm (or ~7.5') annually. In some areas of the northwest portion of the Amazon basin, yearly rainfall can exceed 6000 mm (almost 20')!
Where does all that water go? The water discharged into the Atlantic Ocean is actually only about 1/3rd of the water that falls in the Amazon basin as rain. Where does the other 2/3rds go? Up to half of the rainfall in some areas may never reach the ground, being intercepted by the forest and re-evaporated into the atmosphere. Additional evaporation occurs from ground and river surfaces, or is released into the atmosphere by transpiration from plant leaves. All of this moisture re-enters the water cycling system of the Amazon, and a given molecule of water may be "re-cycled" many times between the time that it leaves the surface of the Atlantic Ocean and is carried by the prevailing westerly winds into the Amazon basin, to the time that it is carried back to the ocean by the Amazon River. The Andes Mountains that border the west side of the Amazon help to ensure that most of the moisture stays in the system - very little is carried by the prevailing winds over the Andes to the Pacific Ocean.
A long and winding river road. The total length of the Amazon River from its source springs in the Andes (taking the Ucayali River as the continuation of the main river into the Andes), is estimated at 6518 km ( ~4075 miles) (not including all river bends, and measuring the short distance around Marajó Island in the mouth of the Amazon). This is exceeded only by the Nile River (including the Kagera River) of Africa with a total length of 6671 km (4170 miles). If you measure the long-way around Marajo Island, however, the Amazon is slightly longer than the Nile! The Amazon headwaters are located high in the Andes at an elevation of about 5,200 meters (17,000 feet), and only 190 kilometers (120 miles) from the Pacific Ocean.
Like mother, like daughters Two of the tributaries of the Amazon, the Juruá and the Madeira Rivers, are both over 3,300 km (2,060 miles) long. About 1,100 other sizeable tributaries empty into the Amazon River.
Talk about a big mouth! The mouth of the Amazon is over 320 km wide (approximately 200 miles), and contains the worlds largest freshwater island, Marajó Island, with an area of 48,000 km2 (about the size of Switzerland).
Momma was not a Rolling Stone! After leaving the Andes, the elevational gradient of the Amazon is very low. Iquitos, Peru is some 3,600 km (2,250 miles) from the Atlantic, yet the river-level at low-water season is only about 100 m (a bit more than 300') above sea-level, and the slope is around 2 cm (less than one inch) vertical change per kilometer. In the lower Amazon, at the mouth of Rio Negro and still 1,500 km from the Atlantic, the river-level at low-water season is only 15 m (~47') above sea-level, and the slope is about 1 cm per kilometer. You won't find any white-water rapids along the main channel of the Amazon, though the sheer weight of the mass of water moves it along at a surprising speed.
NEWS FLASH!! Rumpelstiltskin Drowns in Slow Flood. The Amazon is not a good place to fall into a long deep sleep on the river bank! Seasonal water levels can vary up to 20 meters (65 feet) in the middle Amazon region. Towards the mouth of the Amazon, the yearly change becomes less and less, but even near the mouth of the Amazon (at the Rio Xingu), it is still 4 meters (12 feet). In the Iquitos region of Peru, the annual change in river levels is about 15 meters (~50 as high as 3 meters (9.8 feet) per second.
