Weirs or Barrages | Causes of failure of weirs | Classification of weirs

Weirs or barrages:

A structure which is built across river to increase water level is known as weir. It is also known as barrage.

Barrage:

The different water levels are increased with respect to time then weir is raised and barrages are constructed.

Gates: are constructed to increase the water level. When it is required to increase the water level the gates are closed and vice versa.

Causes of failure of barrage or weir:

• Damage of floor

• Deterioration of floor due to standing waves

• Scour on upstream and downwards

Classification of weir

Weirs are determined by the types of material.

• Vertical drop weir:

It is made up of masonry which is laid over floor.

• Dry stone slope weir:

It is also known as rock fill weir. It is made up of masonry wall.

• Concrete slope weir:

Such a type of weir which is made up of reinforced cement concrete is known as concrete slope weir.