How do rivers form?
Most rivers are formed from rain or snow from glaciers which melt high up in the mountains. Gravity makes the water travel downhill and after many years the water carves a path, creating a river. Some rivers form from lakes such as the Mississippi River in the United States which starts at Lake Itasca.
The passage where a river flows is called a channel. The bottom of the channel is called the river bed and the sides of the river are called a riverbank.
The movement of water in a river is called a current. The current is usually strongest where the river begins.
Beginning, middle and end
Just like a story has a beginning, middle and end, so does a river!
The beginning of a river is called the source or head water. The part of the river that is near the source is called a young river. A young river is normally V-shaped and flows quickly. Young rivers often have lots of small waterfalls and rapids.
The middle part of a river is called a mature river. A mature river is U-shaped. It is much wider than a young river. People use bridges to cross over a mature river.
The end of a river is called the mouth. Rivers usually end in big bodies of water like oceans and lakes.
As a river flows towards its mouth, the land around the river changes from hilly to flat. When the river flows over the flat land it becomes wider and slower. A wide slow river is called an old river. These types of rivers are the best for growing crops.
Changing rivers
Rivers change over time. Floods can make them larger and droughts can make them shrink or dry up. People and animals like beavers can change them too by building dams.
Did you know?
- The longest river in the world is the River Nile in Africa.
- The Amazon River in South America carries the most water of all rivers.
- Rivers can create canyons or gorges. The Grand Canyon in the United States was carved by a strong river.
- Some rivers flow all year round and others only flow in certain seasons.
- There’s a river in South America called Río Negro that has black water.
- Underground rivers form in places where there are lots of cracks in the rocks above. When it rains, the water runs through the cracks and collects in small underground streams.
