Caersws is a large village in the upper Severn valley. It was once an important Roman centre with a military fort.

The River Severn has now reached the middle course of of its journey down to the sea. Here the valley is wider. From Caersws, the River Severn meanders its way through the valley floor to Ironbridge.

Pooh noticed a lot of small stones had collected in front of the bridge pillar.
They are much small than the stones in front of the bridge at Llanidloes. Why?

Rivers reduce their speed when they enter land that is almost flat, such as a wide valley floor. A river drops its load when the speed or volume of the river decreases. Can you see evidence of this in the photo above?

The river bank is made from natural materials. It has been built higher on the side closest to the town. Why do you think this has been done?

Key Vocabulary

Deposition
A river drops its load when the speed or volume of the river decreases. The heavier material is deposited first and the finer material carried further. That is why you will see smaller stones deposited further downstream you go.

Sediment
The material that is carried by a river and then deposited.

Attrition
Materials being carried downstream by the river knock against each other wearing each other smaller. This process is called Attrition.
The further downstream materials are carried the smaller the material gets because of attrition.

Transportation
The movement of the material eroded by the river (called the load) from one place to another.