🕑 Reading time: 1 minuteA canal is an artificial channel constructed to convey water from rivers, reservoirs, etc. for several purposes like power generation, navigation, irrigation, etc. Canals are classified into different types based on factors such as nature of supply source, functions, type of boundary surface, financial output, discharge capacity and alignment of the canal.
- Classification of Canals based on Different Factors
- Based on the Nature of Supply Source
- 1. Permanent Canal
- 2. Inundation Canal
- Based on Functions of Canal
- 1. Irrigation canal
- 2. Power canal
- 3. Feeder canal
- 4. Carrier canal
- 5. Navigation canal
- Based on Type of Boundary Surface of Canal
- 1. Alluvial canal
- 2. Non-alluvial canal
- 3. Rigid Surface canal
- Based on Financial Output
- 1. Protective Canal
- 2. Productive Canal
- Based on Discharge
- 1. Main canal
- 2. Branch Canal
- 3. Major Distributary Canal
- 4. Minor Distributary Canal
- 5. Field Channels
- Based on Canal Alignment
- 1. Ridge Canal
- 2. Contour Canal
- 3. Side-slope Canal
Classification of Canals based on Different FactorsCanals are classified into different types based on factors which are as follows :
- Based on the nature of the supply source
- Based on functions
- Based on the type of boundary surface soil
- Based on the financial output
- Based on discharge
- Based on canal alignment
Based on the Nature of Supply Source
- Permanent Canal
- Inundation Canal
1. Permanent CanalA Permanent canal is a type of canal in which water is available throughout the year. This type of canal is generally directed from a permanent source of supply water bodies. Several Permanent hydraulic structures are constructed in this type of canal for water regulation and distribution. A Permanent canal can also be called as a perennial canal.
2. Inundation CanalInundation canal is a type of canal in which water is available only during the flood periods. These type of canals are taken off from rivers to control the water level in rivers during floods. A canal head regulator is provided to regulate the flow into the canal.
Based on Functions of Canal
- Irrigation canal
- Power canal
- Feeder canal
- Carrier canal
- Navigation canal
1. Irrigation canalA canal aligned along the boundaries of cultivatable areas in order to supply water for the purpose of agriculture is said to be an irrigation canal.
2. Power canalA canal constructed especially for the generation of hydraulic power is termed as power canal.
3. Feeder canalAs the name says, a feeder canal is constructed to feed two or more other canals or branch canals.
4. Carrier canalA carrier canal is multi-function canal which serves the purposes of both irrigation canal and feeder canal. It means the carrier canal feeds the other canals as well as provides water for direct irrigation.
A canal which is constructed especially for navigational purposes is known as navigation canal. The water level required in a navigation canal is generally a lot higher to accommodate large ships, vessels, etc.
Based on Type of Boundary Surface of Canal
- Alluvial canal
- Non-alluvial canal
- Rigid Surface canal
1. Alluvial canalIf the canal is excavated in alluvial soils such as silt, sand, gravel, etc. then it is said to be an alluvial canal.
2. Non-alluvial canalIf the boundary surface of the canal is of non-alluvial soils such as loam, clay, rock, etc. then it is said to be a non-alluvial canal.
3. Rigid Surface canalRigid surface canals also come under non-alluvial canals but here the boundary surface of the canal is lined artificially with a hard layer of lining material such as cement, concrete, stones, etc.
Based on Financial Output
- Protective canal
- Productive canal
1. Protective CanalProtective canals are relief work projects which are constructed to protect a particular area from the shortage of water. The main objective of a protective canal is to fulfill the requirements of cultivators during the period of famine.
2. Productive CanalProductive canals are those which will produce enough revenue for its maintenance and running costs and also to recover the initial investment made on the construction of the canal. It is said to be good if it recovers 6% of its initial investment per annum.
Based on Discharge
- Main canal
- Branch canal
- Major distributary canal
- Minor distributary canal
- Field canal
1. Main canalThe main canal takes off directly from a river or reservoir. It carries water in large amounts to feed the branch and distributary canals. Due to conveying of very high discharge through the main canal it is not recommended to do direct irrigation from it.
2. Branch CanalThe branch canal takes off from main canals at regular intervals. These canals supply water to major and minor distributary canals. The discharge of the branch canal is generally over 5 m3/sec. In the case of branch canals also, direct irrigation is not recommended unless their water carrying capacity is very low.
3. Major Distributary CanalMajor distributary canal takes off from the branch canal or in some cases from the main canal. They supply water to minor distributaries and field channels. A canal is said to be major distributary when its discharge lies between 0.25 to 5 m3/sec.
4. Minor Distributary CanalMinor distributary canal takes off from major distributaries and sometimes directly from branch canals depending upon the discharge of canals. Their discharge is generally below 0.25 m3/sec. These canals supply water to the field channels.
5. Field ChannelsField channels also known as watercourses are small channels excavated by cultivators in the irrigation field. These channels are fed by the distributary canals and branch canals through canal outlets.
Based on Canal Alignment
- Ridge canal
- Contour canal
- Side-slope canal