Rivers, Lakes, and Groundwater

Land waters: rivers, lakes, glaciers, and groundwater.

Rivers

• A river is a natural stream that flows along a channel. Its parts are the source, the tributary, and the mouth. The concepts of river basin and watershed are also important.
• Types of feeding: snow and glacier, rain, mixed.
• The longest river: the Nile (~6650 km), the Amazon (about 6400 km).
• The river with the greatest discharge: the Amazon.

Lakes

Lake	Feature
Caspian	the largest lake (salt)
Baikal	the deepest (1642 m)
Superior	the largest freshwater lake
Dead Sea	the lowest lake, about -430 m

• Baikal: the deepest lake, 1642 m.
• The Aral Sea began to dry up in the 1960s because a large amount of water was taken from the Amu Darya and Syr Darya.

Groundwater

• Unconfined groundwater: above an impermeable layer. It lies closest to the surface, above the first impermeable layer.
• Artesian water: between layers, under pressure. When a well is drilled, it rises to the surface on its own.
• Mineral waters contain many dissolved salts and gases.
• Longest: the Nile, greatest discharge: the Amazon. Do not confuse these two "greatest" records.