Modern methods of irrigation
- 1. NATIONAL INSTITUTE OF TECHNOLOGY , PATNA DEPARTMENT OF CIVIL ENGINEERING WATER RESOURCE ENGINEERING Course: IRRIGATION & WATER MANAGEMENT By SANJAN BANERJEE M.TECH SEMESTAR-1ST Roll- 1625004 MODERN METHODS of IRRIGATION
- 2. 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.
- 3. Types of IRRIGATION IRRIGATION SURFACE FLOW FLOOD PERENNIAL LIFT SUBSURFACE NATURAL ARTIFICIAL
- 4. 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
- 5. 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.
- 6. Modern Methods of Irrigation SPRINKLER IRRIGATION DRIP IRRIGATION
- 7. 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.
- 8. 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.
- 9. LAYOUT OF SPRINKLER IRRIGATION SYSTEM
- 10. COMPONENTS OF A SPRINKLER IRRIGATION SYSTEM
- 11. 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
- 12. 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
- 14. SPRAY PATTERN
- 17. 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.
- 18. 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.
- 19. DRIP IRRIGATION SYSTEM LAYOUT
- 20. 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 Valve 3. Pressure Regulating Valve 4. Pressure Relief Valve 5. Air & Vaccum Release Valve
- 21. 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)
- 22. 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
- 23. 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.
- 24. 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.
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