A river is a natural stream of water which flows in a channel towards a mouth or lake or another river. Rivers have two banks (left and right bank). They have a bed over which the water flows. Rivers always have a source, from where they start. Rivers always flow downhill.

River banks
Rivers have two banks - the right bank and the left bank. If you stand in a river and face the way the water is flowing, the right bank will be on your right hand side and the left bank will be on you left hand side.

River bed
The river bed is the bottom of the river. It can be made of stones, pebbles, boulders, rock and mud. The water flows over the river bed. You can see the river bed in streams, and in the upper course of a river, because the water is shallower. In the middle and lower courses of a river, you cannot see the river bed because the water is much deeper.

In the photo above, the river bed can be seen between the boulders and stones. The boulders and stones also form part of the river bed.

River channel
The river channel is the course for the river water. It can either be a straight channel like a canal, or a meandering channel. The channel gives the river its shape.

Courses of rivers
Rivers have three courses. The course is the journey the river makes to reach the sea. Rivers never have a straight course from source to mouth. Their course is always bendy.

1. The upper course is found in the mountains and hills where the river rises from its source. Often waterfalls and rapids are also found in this course. The river is usually fast flowing in the upper course. There are lots of stones and boulders for the water to flow over. The river starts as a stream in the upper course and flows through V-Shaped valleys.

2. The middle course is where the river starts to become wider and deeper. The land which the river flows over is becoming flatter. The river starts to meander or bend in the middle course.

3. The lower course is where the river becomes its widest and deepest. This course is found closest to the sea where the river has its mouth. The flat area of land by the river banks is known as a floodplain. F armers grow crops there. Sometimes a river can also have an estuary or a delta as its mouth.

Upper course	Middle course	Lower course

Stages of rivers
There are also three stages to a river's life.

1. Stage 1 is a youthful river. This is the river in its upper course where it is fast flowing and is a stream.

2. Stage 2 is the mature river. This is the river in its middle course where it has meanders and is flowing more slowly. Other rivers join as tributaries in its mature stage.

3. Stage 3 is the river in old age. This is the river in its lower course, where it flows slowly towards its mouth at the sea.