This is a picture of the Colorado River near Hoover Dam. Click
on image for full size Rivers are very important to Earth
because they are major forces that shape the landscape. Also,
they provide transportation and water for drinking, washing and
farming. Rivers can flow on land or underground in deserts and
seas. Rivers may come from mountain springs, melting glaciers or
lakes. A river's contribution to the water cycle is that it
collects water from the ground and returns it to the ocean. The
water we drink is about 3 billion years old because it has been
recycled over and over since the first rainfall. A delta is
where a river meets the sea. Usually the river flows more slowly
at the delta than at its start because it deposits sediment.
Sediment can be anything from mud, sand and even rock fragments.
A special environment is created when the fresh water from the
river mixes with the salty ocean water. This is environment is
called estuary. The longest river is the Nile River in Africa,
and the Amazon River