The source is the start, or beginning, of a river. The source of a river is usually found in the hills or mountains. A river can have more than one source. The source is where a river begins its journey.

Types of source
There are many different ways in which rivers can begin:

Springs. Some rivers begin where water flows out of rocks. Rainwater sinks through the soil and trickles through the cracks and spaces in rocks such as chalk and limestone. These are called permeable rocks. The water continues to do this until it reaches a rock like clay. Clay is an impermeable rock.

The water gradually builds up between the boundary of impermeable and permeable rocks. Eventually, it trickles out of the rocks.

The source of the River Len is a spring.

Rills and streams. A lot of rain falls on mountains. Rainwater flows down slopes and quickly makes channels. At first the channels are small. They are called rills. These join together to make bigger rills. Finally a stream is formed. The streams join up to make a river.

Lakes. The source of some rivers is a lake. The source of the River Nile is Lake Victoria, in Burundi.

Melting snow and ice. Water from a melting glacier may be the source of a river. The snow and ice melt when the weather gets warmer. This forms a lake in front of the glacier. The water rushes into channels in the V-Shaped valley and eventually forms a river.

Bogs. In some places, rain water can't sink into the ground as the ground is too wet already. The water forms a bog. The soil and plants nearby soak up the water. the water flows out of the bog to form lakes and streams.

Sources of rivers

• The source of the River Nile is Lake Victoria in Burundi.
• The source of the Missouri river is in the Rocky mountains.
• The source of the Amazon river is in the Andes mountains.
• The Goredale Scar in Yorkshire is an example of a spring.
• The Mississippi has its source in Montana in the USA.