Flooding Irrigation

Flooding Irrigation | Types of Flooding Irrigation | Wild Flooding | Controlled Flooding

 

~ Flooding Irrigation is the type of surface irrigation in which the soil is kept submerged & is thoroughly flooded with water.

~ It is one of the most ancient irrigation methods of irrigation that is still used today.

~ It is common to release the water to the field until the field is covered with water.

~ About 50 % of the total water is lost during the flooding irrigation.

 

Types of Flooding Irrigation

There are two types of flooding irrigation. They are:

1. Wild/Uncontrolled Flooding

2. Controlled Flooding

 

1. Uncontrolled flooding

~ In uncontrolled flooding; the water is spread or flooded into the field without control of water and preparation of land.

~ It is also called wild flooding.

~ The efficiency of this method depends upon the depth of flooding, the size of the stream, the rate of intake of water into the soil, and topography of the field.

 

Suitability:

This method is suitable for inundation irrigation systems, pastures & forage crops which is inexpensive. There should also be the availability of a sufficient amount of water.

 

Disadvantages

1. Inefficient use of water.

2. Uneven distribution of water.

3. Over-irrigation causing the rise of the groundwater table.

4. Large percolation loss.

 

2. Controlled flooding

~ In this type of flooding, water is applied to the land in a controlled manner. There is proper control in the flow as well as in the quantity of water.

 

Types of controlled flooding

Controlled flooding is classified into the following types:

i. Free flooding

ii. Border flooding

iii. Check flooding

iv. Basin flooding

v. Contour laterals

vi. The ZigZag method

 

i. Free flooding

~ Free flooding method is also known as irrigation by plots.

~ The field is divided into several plots of nearly equal levels and water is admitted to these plots at the higher end. The size of the plot depends upon the porosity of the soil.

 

Suitability

This irrigation is suitable:

~ In the area having sufficient amount of cheap water.

~ Relatively flat field

 

Advantages

~ The initial cost of land preparation is less.

 

Disadvantages

~ High labour requirement

~ Water application efficiency is low

 

ii. Border strip method or border flooding

In Border Flooding; the agricultural farm is divided into a series of strips. Strips are about 10-20 m wide and 100-400 m long.

The land is levelled perpendicular to the flow to prevent the concentration of water on either side of the border.

 

Suitability

~ Suitable for all close-growing crops

~ Suitable for row crops & orchards.

 

Advantages

~ Requires less labour & time.

~ Low maintenance cost.

~ Utilizes a large volume of water from the stream to the irrigation field safely.

 

Disadvantages

~ High initial cost

~ Requires proper levelling

~ Requires a huge amount of water

 

iii. CheckĀ  flooding

~ Check flooding is similar to ordinary flooding or free flooding expect that water is controlled by surrounding the check area with flat & low levees.

~ If the ground has some initial slope, levees may follow the contour. It is suitable to irrigate food & grain crops in heavy soil.

 

Suitability

~ This method is suitable for both permeable and impermeable soil. If soil is permeable, water can be spread easily without any percolation losses. If the soil is impermeable, water can be held for a long time.

 

Advantages

~ High irrigation efficiency can be achieved.

~ Unskilled labour can be employed.

 

Disadvantages

~ Large numbers of labours are required.

~ Levees restrict the use of modern machinery.

 

iv. Basin flooding

It is a special type of check flooding. This method of irrigation is used to irrigate orchards & large trees. One or more trees are generally placed in the basin & the surface is flooded as in check method.

 

Suitability

~ It is suitable for orchards and trees.

 

Advantages

~ Less labour.

~ Less maintenance cost.

~ Provide efficient use of water.

 

Disadvantages

~ High initial cost.

~ A large quantity of water needed.

~ Requires levelling.

 

v. Contour laterals

This method is best suited in steeper terrain. The field is cut by a relatively dense network of contour laterals.

Space of contour laterals depends upon the grade of land, uniformity of slope & type of soil.

 

Suitability

~ For close-growing crops on slopy land.

 

Advantages

~ It can be used in all types of soils

~ Low cost

 

Disadvantages

~ Inefficient use of water.

~ Uneven distribution of land

~ Over-irrigation

~ Large percolation

 

vi. Zigzag method

The Zigzag method is a special method of controlled flooding where water applied to the land takes a circuitous route, starting from the field channel and reaching the dead end of each plot.

For this purpose, the whole farm is divided into several squares (or rectangular) plots. Each plot is provided with levees ( or small bunds ) such that the water takes the circulation path covering the entire plot.

The Zigzag method is quite suitable for relatively level plots. However, the method is not suitable when the farming operations are to be done with modern farm machinery.

 

Read More: Furrow Irrigation

Read More: Duty in Irrigation

 

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