Types Of Canal | Classification Of Canal | What Is Canal?

What Is Canal?

A canal is an artificial passage used for the conveyance of water from a river or from a reservoir to its intended destination for the intended use. Canals are also known as channel, which is derived from the French word “Chanel”.

A canal connects a river or a reservoir to the destination where the water is to be supplied. Water in the canal is conveyed for various purposes such as irrigation, power generation, etc. 

Canals are also used for the passage of boats or ships, nowadays. Canals are usually constructed in a trapezoidal shape. Canals are lined using different materials like concrete, brick, stone, or flexible membrane which helps in the prevention of water seepage and also prevents soil erosion.

There are various types of canals based on different factors. Let us learn about its classifications in detail below.

Classification Of Canals

Based on various considerations, canals are classified as follows:-

1. Classification of canals based on the nature of the source of supply.
2. Classification of canals based on their function.
3. Classification of canals based on discharge and relative importance.
4. Classification of canals based on financial output.
5. Classification of canals based on their alignment.
6. Classification of canals based on the nature of the source of supply.

Based On The Nature Of Source Of Supply:

canals are further classified as:-

1. Permanent canal
2. Inundation canal

Permanent Canal

A permanent canal is the one which has the availability of water throughout the year. A permanent canal is also known as a perennial canal. It is provided with permanent regulations and distribution works. A permanent canal is generally directed from a permanent source of water supply.

Inundation canal

An inundation canal is a type of canal which gets its supply of water only when the rivers or the reservoirs are flooded. An inundation canal is not provided with any kind of headworks to divert the river water to the canal. However, a canal head regulator is provided for controlling the discharge in the canal.

Classification Of Canals Based On Their Functions

Based on its functions, canals are further classified as:

1. Feeder canal
2. Carrier canal

Feeder Canal

A feeder canal is constructed to feed two or more canals or their branches. Direct irrigation is not done from a feeder canal. An example of a feeder canal is the Indira Gandhi feeder canal. It is 216 km long, which takes off from Harika barrage across river Sutlej (Punjab) and feeds Indira Gandhi canal.

Carrier Canal

A carrier canal serves the purpose of feeder canal as well as it also provides the water for direct irrigation. It is hence a multipurpose canal. The Upper Chenab canal in west Punjab, Pakistan is one of the examples of carrier canal.

Classification Of Canals Based On Discharge And Relative Importance

Based on discharge and relative importance, canals are further classified as:

1. Main canal
2. Branch canal
3. Major distributary
4. Minor distributary
5. Watercourse

Main Canal

It is the principal canal of the network of canals. It is directly connected to the source of water i.e. the river or the reservoir. It carries a heavy discharge, directly from the source of water and supplies the water to major distributaries and the branch canals connected to it. The main canal is not used for direct irrigation.

Branch Canal

The branch canal is the one which is connected to the main canal. It receives the water supply from the main canal. Like the main canal, the branch canal does not carry out direct irrigation but acts as a feeder canal for major distributaries and minor distributaries as well. The branch canals usually carry a discharge of over 5 cumecs.

Major Distributary

In the canal network, the major distributaries take off from the branch canals or from the main canals too. It carries a discharge ranging from 0.25 cumecs to 5 cumecs respectively. The major distributaries are also used for direct irrigation. They supply the water through outlets to watercourses.

 Minor Distributary

These are usually connected to the major distributaries of the branch canals. The canals which carry a discharge of less than 0.25 cumecs are referred to as the minor distributaries or minors. Minor distributaries supply water to the watercourses.

Water Course

It is a small channel, also known as a field channel, which is connected to the minor distributary on one side and the field on the other side. Field channels are the one which directly supplies water to the field. These channels are owned, constructed, controlled and maintained by the cultivators.

Classification Of Canals Based On Financial Output

Based on the financial output, canals are further classified as:

1. Productive canal
2. Protective canal

Productive Canal

Productive canals are the types of canals which generates a certain revenue to the nation when it is fully developed. The generated revenue will help to cover up the cost of construction, cost of maintenance, and its running cost respectively.

Protective Canal

These are constructed to provide relief in the form of the supply of water during the time of famine. When there is a shortage of water, these canals provide sufficient water to the affected area and also have a storage of water which can be utilized in future.

Classification Of Canals Based On Their Alignment

Based on their alignment, canals are further classified as:-

1. Contour canal
2. Ridge canal
3. Side slope canal

Contour Canal

A contour canal is a type of canal aligned nearly parallel to the contour of the area.

Ridge Canal

A ridge canal is also known as a watershed canal. This canal is the one which is aligned along the watershed.

 Side Slope Canal

It is the one which is aligned at the right angles to the contours of the country.

Also Read –

Types & Methods Of Irrigation

Sprinkler Irrigation System

Drip Irrigation System

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