Rivers and their formation.
River, any body of fresh water flowing from an upland source to a large lake or the sea, fed by such sources as springs and tributary streams. The main parts of a river Include a channel, which the water flows, and llat region of a valley on either side of the a a water and channel. Through lhe channel and floodplain, sediment material transported by the river, such as sand and silt-are transferred from ridges and mountains to the a lake river starts on as small channels, sea or to larger channels or tributaries come rills combine to make The largest channels that eventually together, forming distinct streams can carry formed by this convergence of tributaries are rivers. and they large quantities of fresh water and sediment across continent Large rivers are located on every continent. The longest on is the river E Nile River in Africa, with a length of 6,695 km (4,160 mi) from headwaters Burundi to its in its mouth at the Mediterranean Sea. The Nile River basin covers an area of 3,349,000 sq km (1,293,000 sq mi. The Amazon RIver in South America carries the largest amount of water and runs for a length of 6,400 km (4,000 mi. This single river contributes 20 percent of the river water that flows into the world’s oceans. The Yellow River (or Huang He) in China gets its name from the yellow sediments of the soils of central China, and it carries the largest amount of sediment to the ocean The Yellow River is the second longest river in China, at 5,500 km (3,400 mi), after the Yangtze, which is 6,300 km (3.900 mi long Since the continents formed millions of years ago, rivers have been important geologic forces as conveyors of water and sediment. The rise of human civilization is intimately linked to rivers for access to drinking water, irrigation, transportation, and fisheries. People have irrevocably altered the landscape by maintaining rivers for navigation, constructing irrigation works, and building dams for hydroelectric neration scientists study (iver systems as they are important to the flow offor navigation, constructing irrigation works, and building dams for hydroelectric power generation. Scientists study river systems as they are important to the flow of fresh water over wide areas of land (and eventually into our homes) and across continents. Rivers are also an important part of sensitive habitats, especially wetlands. The study of rivers is necessary to ensure the protection of ecologically important habitats.