Month: October 2017

Chute Spillway Definition/About Chute Spillway

What is Chute Spillway

The chute spillway is also known as the “through spillway”. A chute spillway consists of an open channel, by which water is conveyed from the reservoir to the river or to Nalla below the dam, through a fairly steep slope.

The chute spillway is the simplest type of spillway which can be easily provided independently and at low costs. It is lighter and adaptable to any type of foundation and hence provided easily on earth and rockfill dams.

A chute spillway is sometimes known as a waste weir. If it is constructed in continuation to the dam at one end, it may be called a flank weir. If it is constructed in a natural saddle on a bank of the river separated from the main dam by a high rigid, it is called a saddle weir.

Definition Of Cross Drainage Work

The canal may have to cross the natural drainage like rivers, streams, etc. at different points within the command area.

To dispose of canal and drainage water safely, we need to construct a structure at the crossing point.

A cross-drainage work is a structure that is constructed at the crossing of a canal and a natural drain, to dispose of drainage water without interrupting the continuous canal supplies.

Divide Wall And Their Function

What is Divide Wall?

The divide wall is masonry or a concrete wall constructed at a right angle to the axis of the weir and separates the weir proper from the under sluices.

The top width of the divide wall is about 1.5 to 2.5 m. These walls are founded on wells closely spaced beyond the pucca floor up to the end. the wells are taken well below the deepest possible scour.

Functions of Divide Wall

The main functions served by the divide wall are:

1. It separates the under sluices from the weir proper since the crest level of the under sluices is lower than that of the weir proper, the two must be separated and this is being done by the divided wall.

2. It helps in providing a comparatively less turbulent pocket near the canal head regulator, resulting in deposition of silt in this pocket and thus to help in the entry of silt-free water into the canal.

Read More:

Diversion Headwork

Definition Of Barrage And Their Advantages and Disadvantages

Definition Of Barrage

A barrage is an artificial barrier across the river to prevent flooding, aid irrigation, navigation, or generate electricity by tidal power.

Advantages of Barrage

1. The barrage has good control over the river during the flood. The outflow can be easily regulated by gates.

2. There is good control over silt entry into the canal.
3. A roadway can be conveniently provided over the structure at a little additional cost.

Disadvantages of Barrage

1. The initial cost of the barrage is quite high.

Definition Of Weir And Their Advantages and Disadvantages

Definition Of Weir

A weir is a raised concrete crest wall constructed across the river to raise the water level in the river and divert the water into the canal.

Advantages of Weir

1. The bed level of the canal may be higher than the existing water level of the river. In such cases, the weir is constructed across the river to raise the water level.

2. Adjustable shutters are provided on the crest to raise the water level to some required height.
3. The initial cost of the weir is low

Disadvantages of Weir

1. Low control on flow.
2. No provision for transport communication across the river.
3. Chance of silting on the upstream is more.

Weir and Barrage – MCQ