There are many meanders around Caersws because the river is now flowing across low land. The River Severn begins to wander from side to side across the valley floor. The main erosion seen here tends to be horizontal (sideways), rather than the vertical erosion seen in the mountains.

A meander is a bend in a river. Meanders normally occur in the middle and lower courses where the water is moving more slowly.

Over long periods of time the shape of these meanders will change, due to erosion and deposition.

The river has cut through a loop, forming an ox-bow lake

An ox-bow lake has formd here
The River Severn used to travel more to the right in the photo above, but has now broken through and changed course. Click on the old river bed in the photo above to have a closer look.

On the inside of the bend, where the river flow is slower, material is deposited.

The river meanders to the left.

Berty notices some stones and clumps of earth by the bank in the river.
Where do you think they came from?

Outside of bend where most erosion occurs

The force of the water erodes and undercuts the river bank on the outside of the bend where water flow has most energy (flows faster). The force of the water crashing into the bank is wearing away the river bank. This is even more noticeable when the Severn is in full flood.

The river continues to meander its way through the Caersws floodplain carving out S-shaped bends.

The photo above shows a meander belt

A meander belt is where there are several meanders occurring one after the other.

Follow this link to find out more about the ox-bow lake at Caersws

Meander Animation
A simple animation of a fairground ride to help pupils understand the concept of objects being thrown outwards on a bend.

Meander Animation
The basic features of how a meander is formed.

Key Vocabulary

Erosion
Erosion is the wearing away of sides and bottom of the rivers by the force of the water, and material carried by the water.

Hydraulic Action
This is like pointing a jets spray at the bank. The power and force of the water crashing into the river banks wears them away.

Meander
A meander is a wide, looping bend in a river

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