What are the types of weir?

Types of Weirs

• Types of Weirs based on Shape of the Opening. Rectangular weir. Triangular weir. Trapezoidal weir.
• Types of Weirs based on Shape of the Crest. Sharp-crested weir. Broad- crested weir. Narrow-crested weir. Ogee-shaped weir.
• Types of weirs based on Effect of the sides on the emerging nappe.

What is weir in irrigation?

Weir is a low obstruction that is built across a river or canal to raise the water level, or in parallel to divert the water. The in-stream weirs are widely used to measure the rate of flow. At flow rates above the threshold flow rate the water level rises above the level of the diversion weir and water is diverted.

How is weir length calculated?

The Length is the bottom width of the weir. The height is measured from the bottom of the weir opening to the top of the water level ponded behind the weir (not the water level right as it leaves the weir).

What is the weir used for?

Weirs are fixed barriers across a river or stream that force water to flow over their tops, where the height of the water above the weir can be used to calculate flow.

How are weirs used to change water flow?

A weir is a concrete or masonry structure which is constructed across the open channel (such as a river) to change its water flow characteristics. Weirs are constructed as an obstruction to flow of water.

What are the different types of weirs used for?

This often prevents weirs from being used in flat canals or ditches, or canals with little head upstream. Weirs are available in a variety of shapes and sizes, but the most common and most simple are the Rectangular, Cipolletti, and the V-Notch weirs. The style of weir required depends on your particular application.

How big does a weir need to be to hold water?

For more information, download the Weir PDF here. + Reinforced Checks are designed and built sturdy enough to withstand the greater strain of holding water in deeper ditches. + Though strong enough to hold up to a 36in head of water, they can easily be moved to wherever water flow must be controlled.

How to find the discharge over a weir?

The top edge of weir may be sharp crested or narrow crested. It is generally suitable for larger flowing channels. To find the discharge over rectangular weir, consider an elementary horizontal strip of water thickness dh and length L at a depth h from the water surface.