Explanation:

Direct Irrigation:

• In a direct irrigation system, water is directly diverted from river into canal by construction of a diversion weir or barrage across river without attempting to store water. This method is practiced where river has an adequate perennial supply to feed canal system during times of crop periods.

Diversion-Based Irrigation or Diversion scheme:

• Diversion Based Irrigation (DBI) is a simple and cost-effective method, in this method we use slope or gravity (or gravitational force) to guide water from adjacent streams and rivers to cropping field areas. It comes under a direct irrigation system.

Additional Information

Storage Irrigation:

• Storage irrigation is also known as tank irrigation. Tanks are small-sized reservoirs formed by small earn embankments to store runoff for irrigation. The site is selected within a watershed protected by vegetation and containing a minimum of cultivated land so as to ensure a minimum rate of sedimentation which lowers its storage capacity. It is more popular in peninsular region in states of Karnataka, Maharashtra, and Tamil Nadu.

Flow Irrigation:

• When water is available at a higher level, and it is supplied to lower level, by mere action of gravity n it is called flow irrigation.

Inundation Irrigation:

• Inundation irrigation is done by a canal taking off from a river in flood without any diversion work. It depends on periodical rise in water level of river and supply is drawn through open cuts in river bank or creeks which are called heads.

Explanation:

Surface Irrigation System:

We have two sources of water to be used as irrigation water one is ground water and or is flowing water. Based on source of water used as irrigation water, water irrigation system is mainly divided in to two categories:

1. Lift irrigation – when ground water lifted up to be used as irrigation water ( Eg: Well Irrigation)
2. Flow irrigation – when flowing water is used as irrigation water.

These are furr classified as below – 

Note:

Methods of Irrigation systems:

Irrigation water may be applied to crops by three basic methods:-

1. Surface Irrigation method

2. Sprinkler irrigation method

3. Sub-surface irrigation method

Explanation:

Irrigation is process of applying water to crops artificially to fulfil ir water requirements. Nutrients may also be provided to crops through irrigation.

Types of irrigation: Irrigation may broadly be classified as follows:

(A) Surface Irrigation: In this type of irrigation water wets soil surface. It can be furr classified into:

(1) Flow Irrigation: 

• When water is supplied from higher level to lower level by action of gravity n it is called flow irrigation. The irrigation from canal water or river water is example of flow irrigation.

(2) Lift Irrigation: 

• When water is lifted up by any manual or mechanical means such as Persian wheel, pumps, etc. and n supplied for irrigation n it is called lift irrigation.

(B) Sub-surface Irrigation:

• In this type of irrigation, water does not wet soil surface.
• In this system of irrigation supplied water comes directly in touch with root zone of crops.
• Sub surface irrigation may be classified into two types:
  • ?Natural Sub-irrigation: When underground irrigation can be achieved simply by natural processes without any extra efforts it is called natural sub-Irrigation.
  • Artificial Sub-irrigation: The open jointed system of drain is artificially laid below soil so as to supply water to crop by capillary action, n it is known as artificial sub-irrigation. This process is not adopted in India because it is very costly.

Additional Information

Flow irrigation can be furr subdivided into :

(a) Perennial Irrigation: 

In this type of irrigation system, water requirement for irrigation is supplied constantly and continuously in accordance with crop requirements throughout crop period.

Perennial canal system may be furr sub-divided as follows : 

• Direct Irrigation: When irrigation is done from direct run off of a river, or by diverting  river run off water into some canal by constructing a diversion weir or barrage across river. For example, Ganga Irrigation canal system.

• Storage Irrigation: When a dam is constructed across a river to store water during  monsoon and stored water is supplied in off taking channels during periods of low flow, it is called storage irrigation.

?(b) Flood Irrigation: 

This kind of irrigation is some times called as Inundation irrigation. In this method of irrigation soil is kept submerged and flooded with water, so as to cause thorough saturation of land.

Explanation:

Irrigation is process of applying water to crops artificially to fulfil ir water requirements. Nutrients may also be provided to crops through irrigation.

Types of irrigation: Irrigation may broadly be classified into : (1) Surface Irrigation  (2) Sub-surface irrigation

(1) Surface Irrigation: In this type of irrigation water wets soil surface. It can be furr classified into:

• Flow Irrigation: When water is supplied from higher level to lower level by action of gravity n it is called flow irrigation. The irrigation from canal water or river water is example of flow irrigation.
• Lift Irrigation: When water is lifted up by any manual or mechanical means such as Persian wheel, pumps, etc. and n supplied for irrigation n it is called lift irrigation.

?

Flow irrigation can be furr subdivided into : (a) Perennial Irrigation  (b) Flood Irrigation

(a) Perennial Irrigation: In this type of irrigation system, water requirement for irrigation is supplied constantly and continuously in accordance with crop requirements throughout crop period.

Perennial canal system may be furr sub-divided as follows : 

• Direct Irrigation: When irrigation is done from direct run off of a river, or by diverting  river run off water into some canal by constructing a diversion weir or barrage across river. For example, Ganga Irrigation canal system.

• Storage Irrigation: When a dam is constructed across a river to store water during  monsoon and stored water is supplied in off taking channels during periods of low flow, it is called storage irrigation.

?(b) Flood Irrigation: This kind of irrigation is some times called as Inundation irrigation. In this method of irrigation soil is kept submerged and flooded with water, so as to cause thorough saturation of land.

(2) Sub-surface Irrigation:

• In this type of irrigation, water does not wet soil surface.
• In this system of irrigation supplied water comes directly in touch with root zone of crops.
• Sub surface irrigation may be classified into two types:
  • ?Natural Sub-irrigation: When underground irrigation can be achieved simply by natural processes without any extra efforts it is called natural sub-Irrigation.
  • Artificial Sub-irrigation: The open jointed system of drain is artificially laid below soil so as to supply water to crop by capillary action, n it is known as artificial sub-irrigation. This process is not adopted in India because it is very costly.

Explanation:

Water distribution efficiency:

• Water distribution efficiency is also known as uniformity coefficient.
• It is  measure of how uniformly water is applied to area being irrigated.
• The effectiveness of irrigation is measured by its uniformity coefficient.

Water distribution efficiency $={\eta }_d=[1-\frac{y}{d_w}]\times 100$

 d_w = average depth of water stored

 y= Average of absolute value of deviations

 Y₁, Y.,...., Y_n absolute deviations from average depth of water stored

Additional Information

The various types of irrigation efficiencies are given below:
1. Water Conveyance Efficiency:

• It is ratio of water delivered to field (W) to water diverted from reservoir (W). Mamatically it is given as:
•  (Water Delivered to field / Water diverted from reservoir)
•  Water diverted from reservoir - Water delivered to field = seepage loss in canal + Evaporation from canal.

2. Water application Efficiency:

• It is ratio of water stored in root zone (W_s) to water delivered to field (W). Mamatically it is given as:
• ( Water stored in root zone /Water Delivered to field)
• Water delivered to field - Water stored in root zone = Runoff + Evaporation

3. Water Used Efficiency:

• It is ratio of water used consumptively to water delivered in field. (or) It is yield of crop per unit of water lost through evapotranspiration of crop.
• (Water used consumptively Water Delivered to field)
•  Water Used = Water stored (W_s) – leaching – or requirements

4. Water Storage Efficiency:

• It is ratio of water actually stored in root zone and water which is to be stored in root zone to bring water content to its field Capacity.
•  (water actually stored in root zone/ Water is to be stored in root zone to bring water content to its field capacity) 

Furrow is a long, narrow irrigation trench made in ground used for an optimal supply of water.

Furrows can be level and are very similar to long narrow basins. However, a minimum grade of 0.05% is recommended so that effective drainage can occur following irrigation or excessive rainfall.

Important points:

Explanation:

Method of irrigation: 

1) Free flooding

2) Border flooding

3) Basin flooding

4) Farrow irrigation

5) Sprinkle method

6)Drip irrigation

7) Check flooding: It is similar to free flooding except that water is controlled by surrounding check area with low and flat levees. This method is suitable for more permeable soils as well as for less permeable soils because water can be quickly spread in case of high permeable soils, thus reducing percolation losses. 

Direct irrigation: in this method, water is directly diverted from river without being stored at any point. It is used when river is perennial in nature.

Storage irrigation: This method is used when river is seasonal in nature. Hence for continuous irrigation, excess water is stored.

Lift irrigation: In this method, water is not transported by natural flow but it is lifted with help of pumps or or means.

Concept:

Irrigation Projects in India are classified into three major aspects:

• Major Irrigation Projects: A project having a cultivable command area(CCA) of more than 10,000 hectares.
• Medium Irrigation Projects: A project having CCA between 2000 and 10,000 hectares.
• Minor Irrigation: A project with is designed to irrigate an area of 2000 hectares or less is classified as a minor irrigation 

Note:

Whereas major and medium irrigation works are meant for tapping surface water (e.g., rivers), minor irrigation mainly involves groundwater development, e.g., tube-wells, boring works, etc.

Explanation:

In free flooding, Ditches are excavated in field eir on contour or up and down slope. This method is suitable for close growing crops, pastures etc. This method is suitable on rolling land of irregular topography, where or methods are not suitable.

It is also called wild Flooding

Additional Information In Border flooding,  land is divided in to number of strips, separated by low levees called borders.

Check flooding is similar to ordinary flooding except that water is controlled by surrounding check area with low and flat levees. This method is suitable for more permeable soils as well as for less permeable soils.

In furrow flooding method, only one-fifth to one-half of land surface is wetted by water. In this method, evaporation loss is very low.