NATIONAL INSTITUTE OF TECHNOLOGY , PATNA

DEPARTMENT OF CIVIL ENGINEERING WATER RESOURCE ENGINEERING

Course: IRRIGATION & WATER MANAGEMENT

By

SANJAN BANERJEEM.TECH

SEMESTAR-1STRoll- 1625004

MODERN METHODS of IRRIGATION

WHAT IS IRRIGATION? It is defined as the science of artificial

application of water to the land , in accordance with ‘crop requirements’ throughout the ‘crop period’ for full fledge nourishment of the crops.

Types of IRRIGATION

IRRIGATION

SURFACE

FLOW

FLOOD

PERENNIAL

LIFT

SUBSURFACE

NATURAL

ARTIFICIAL

IRRIGATION IN THE PAST Farming was more focused on subsistence rather than

selling products in the market. Labor intensive. Irrigated land used to be small. Highly dependent on weather & Inefficient.

More focus is now on selling the output. Machine intensive & more sophisticated. Rains are no longer the controlling force.

MODERN CONSIDERATIONS

Objective for Modern Methods:

Artificial control over supply of water.

Low losses & High Efficiency.

Less labour requirement & degree of freedom over

MANPOWER MANAGEMENT.

Water Application Efficiency as well as Distribution

Efficiency is very high.

Simontaneous injection of Fertilizer & Pesticides.

Modern Methods of Irrigation

SPRINKLER IRRIGATION

DRIP IRRIGATION

SPRINKLER IRRIGATION

Consists of a network of pipes and sprinklers spaced at suitable

places.

At the nozzle Pressure head is converted to Velocity head.

Area of Land wetted depends on following factors i.e. judges

‘Efficiency’ 1. Velocity of water Jet

2. Angle of Flow

3. Type of Sprinkler & it’s design

4. Wind Speed & Direction.

Just like artificial application of Rain.

Sprinkler Continues….

ADAPTABILITY Irregular Topography i.e. unsuitable for Surface Irrigation. Gradient is Steeper. Highly Sandy soil or Highly Clayey Soil. High water table i.e. near to ground. Seasonal Water demand is low for that area. Crops having following Factors

1. Required Humidity Control (Tobacco).2. Having shallow roots.3. Required high & frequent irrigation.

LAYOUT OF SPRINKLER IRRIGATION SYSTEM

COMPONENTS OF A SPRINKLER IRRIGATION SYSTEM

COMPONENTS continues…

1. Pumping Set 2. Main Line

3. Lateral Line 4. Sprinkler Heads

5. Debris Screenes 6. Desilting Basins

7. Booster Pump 8. Take-off Valves

9. Flow Control Valve

TYPES OF SPRINKLER IRRIGATION SYSTEM

1. Rotating Head System

A. Portable system

B. Semi-portable system

C. Solid Set system

D. Semi Permanent System

E. Permanent System

2. Perforated Type System

3. Centre Pivot System

CENTRE PIVOT SYSTEM

SPRAY PATTERN

SPRAY PATTERN continues…

VARIATION IN PRESSURE

DRIP IRRIGATION

Also known as TRICKLE Irrigation

Water is applied frequently but at a slow rate (<14lit/hr)

Dia. of pipe & Emitters are small compared to Sprinkler Irrigation

No need for separate drainage System.

Full control over Weeds.

Ferti-gation possible.

Some Salient Points….

Acceptable to any Farmable slope.

Crop & Drippers are placed on contour lines to minimize

discharge.

In Clayey soil, water application rate should be low.

In Sandy Soil, Water Application Rate should be moderate.

If water is not clean, then system may chocked. Deposition of

Fertilizer (Ca & Na precipitate) would also cause chocking.

Suitable sand filters needed to counter chocking.

DRIP IRRIGATION SYSTEM LAYOUT

COMPONENTS OF A DRIP IRRIGATION SYSTEM

1. Drippers 2. Valves 3. Filters 4. Main line 5. Sub-Main line 5. Lateral Line 6. Pump 7. Fertilizer tank (if any)

Valves Used:

1. Flow Control Valve 2. Non Return Valve3. Pressure Regulating Valve 4. Pressure Relief Valve5. Air & Vaccum Release Valve

Drippers & Types

Operating Pressure: 1. Low Pressure Dripper (Pr

<0.8m)

2. Medium Pressure (2<Pr<8m)

3. High Pressure (8<Pr<15)

Path Cross Section: 1. Low (<0.8mm)

2. Medium (0.8 to 1.5mm)

3. Wide (above 1.5mm)

TYPES of DRIPPERS continues…

Discharge Rates: 1. Low ( Q < 4lit/hr)

2. Medium (4 <Q <10Lit/hr)

3. High (Q < 15lit/hr)

Different types of Emitter: 1. Compensating

2. Continouas Flushing 3. Flushing

4. Long Path 5. Multi-outlet

6. Orifice 7. Vortex

MAINTAINANCE OF DRIP IGRRIGATION SYSTEM

Flushing of Sub-mains & Laterals: Frequently done for Low

Discharge & rarely done for High Discharge System to removed entrapped Silt or

Sand in pipe.

Chemical Treatment: Applied when clogging was due to precipitation

of dissolved salt like Carbonate, Bi-carbonate of Ca, Fe, Na & Sulphur Slimes of

Bacteria.

Acid Treatment: HCl is applied till pH-4 is observed and system is

closed for 24hrs.

Chlorine Treatment: Has to be done in the form of Bleaching Powder

to avoid growth of Bacteria.

REFERENCES

Bibliography:

Michel A.M. (2011, 2nd edition), Irrigation Theory and Practice, Vikas Publishing House Pvt. Ltd. , New Delhi. Garg S.K. (28th edition), Irrigation Engineering and Hydraulic Structures, Khanna Publishers, New Delhi.

THANK YOU