The River Avon has joined the River Severn

Tewkesbury town in the distance

Locks and Weirs

A lock and weir system is needed on the River Severn to control the flow of water and to make sure enough water is kept back to enable boats to navigate rivers better.

Large sign on the bank

This weir has various functions including:

• churning the water up, causing it to take in air for fish to breath
• Keeping water back - the water level above the weir is kept deeper for boats to navigate better.
  

The water from the weir joins up with the water from the lock

Key Vocabulary

Flood Plain
An area of flat land found on either side of a river and which are regularly flooded whenever a river spills over its banks.

Weir
A weir is an artificial wall built across a river in order to make the river deeper. A weir is a small type of dam and it looks like a waterfall because water flows over the top of the weir.

Lock
A part of a canal or river that is closed off by gates. The water level in a lock can be changed. A lock is used to raise and lower the boats that are travelling through it. Often found situated next to a weir.

Navigable
A river is said to be navigable when it is suitable for boats.