Methos of irrigation

its only overview.

1. Government Engineering College , Patan Department :- Civil Engineering Subject :- Irrigation Engineering (2170609) Topic :- Methods Of Irrigation SR. NO. NAME Enrolment No. 1 Patel Brijesh S. 160220106027 2 Suthar Vivek K. 160220106054 3 Patel Siddhi A. 160220106039 4 Patel Vimal H. 160220106040 5 Rabari Mayur J. 160220106045

2. What is Irrigation? Irrigation is defined as the process of artificially supplying water to soil for raising crops. Irrigation engineering is the science dealing with planning, designing, construction, operation, and maintenance of various irrigation works. “ Irrigation is the primary consumer of water on earth ” Igor A. Shiklomanov (Russian Hydraulogist )

3. Traditional irrigation method : Moat : Also called the pulley system, it involves pulling up water from a well or other such source to irrigate the land. It is an extremely time consuming and labour intensive system, but it is very cost efficient. Also, wastage of water is avoided when using a moat system of irrigation. Chain pump : A chain pump consists of two large wheels connected by a chain. There are buckets attached to the chain. One part of the chain dips into the water source. As the wheel turns, the bucket picks up water. The chain later lifts them to the upper wheel where the water gets deposited into a source. And the empty bucket gets carried back down.

4. Dhekli : It is a system of drawing water from a well or such similar source. Here we tie a rope and bucket to a pole. At the other end, we tie a heavy stick or any other object as a counterbalance. And we use this pole to draw up water. Rahat : Rahat system of irrigation uses animal labour. Above the well, we tie a large wheel. An ox or cow would turn the wheel to draw the water from the well.

5. Moat

6. Methods Of Irrigation

7. Surface Irrigation : Water is applied to the soil surface and the water flow by gravity either through furrows, strips or basins. Water is applied from a channel located at the upper reach of the field. Loss of water by conveyance and deep percolation is high and the efficiency of irrigation is only 40-50% at field in this type of method. Properly constructed water distribution systems to give sufficient control of water to the field. Effective land preparation to permit uniform distribution of water over the field are very important. Low initial cost of development is later offset by high labour cost of applying water.

8. Flooding Method : Uncontrolled flooding method : When water is applied to the cropland without any preparation of land and without any levees to guide or restrict the flow of water on the field, the method is called ‘uncontrolled’, ‘wild’ or ‘free’ flooding. Controlled flooding method : When water is applied by spreading it over the land to be irrigated with proper control on the flow of water as well as the quantity of water applied, the method is called ‘controlled flooding method’.

9. Free flooding method : Ditches are excavated in the field either on the contour or up and down the slope . It is also called wild flooding , since no attempt is made to control the flow of water by means of levees, etc. Characteristics : land preparation cost is low . labour requirements are usualIy high . water application efficiency is also low. Most suitable for close growing crops, pastures, etc., particularly where the land is steep. Spacing between contour ditches /laterals /subsidary ditches is kept 20 to 50 m.

10. Border strips : In this method, the land is divided into a number of strips, separated by low levees called borders. Strip size: 10 to 20 m wide, and 100 to 400 m long . To prevent water from concentrating on either side of the border, the land should be leveled perpendicular to the flow. Water is made to flow from the supply ditch into each strip . The water flows slowly towards the lower end, and infiltrates into the soil as it advances . When the advancing water reaches the lower end of the strip, the supply of water to the strip is turned off.

11. Check basins : Check flooding is similar to ordinary flooding except that the water is controlled by surrounding the check area with low and flat levees . Levees are generally constructed along the contours, having vertical interval of about 5 to 10 cm. These levees are connected with cross-levees at convenient places as shown in Fig. The confined plot area varies from 0.2 to 0.8 hectare . This method is suitable for more permeable soils as well as for less permeable soils. The water can be quickly spread in case of high permeable soils, thus reducing the percolation losses.

12. Basin flooding : This method is a special type of check flooding and is adopted specially for orchard trees. One or more trees are generally placed in the basin, and the surface is flooded as in check method, by ditch water, as shown in Fig.

13. Contour farming : Contour farming is practiced in hilly areas with slopes and with falling contour. The land is divided into series of horizontal strips called terraces. Small bunds are constructed at the end of each terrace to hold water up to equal height. Contour farming besides producing crop yields, helps in mitigating indirectly controlling flood, soil conservation.

14. Zig-zag Method : In this method, the agricultural area is sub- divided into small plots by low bunds in a zig- zag manner. The water is supplied to the plots from the field channel through the openings. The water flows in a zig- zag way to cover the entire area. When the desired depth is attained, the openings are closed.

15. Furrow method : Furrow irrigation - in which the water poured on the field is directed to flow through narrow channels dug between the rows of crops, instead of distributing the water throughout the whole field evenly. The furrows must all have equal dimensions, in order to guarantee that the water is distributed evenly. Like flood irrigation, furrow irrigation is rather cheap in areas where water is inexpensive.

16. B. Sub-surface Irrigation :- Applied in places where natural soil and topographic condition favour water application to the soil under the surface, a practice called sub-surface irrigation. These conditions include : Impervious layer at 15 cm depth or more. Pervious soil underlying the restricting layer. Uniform topographic condition. Moderate slopes. The operation of the system involves a huge reservoir of water and level is controlled by inflow and outflow. The inflow is water application and rainfall while the outflow is evapotranspiration and deep percolation. It does not disturb normal farm operations. Excess water can be removed by pumping.

17. Natural & Artificial sub-surface irrigation : Natural Irrigation :- Subsurface irrigation or sub-irrigation may be natural or artificial. Natural sub surface irrigation is possible where an impervious layer or loose surface exists below the root. Artificial Irrigation :- In artificial sub surface irrigation, perforated or porous pipes are laid out underground below the root zone and water is led into the pipes by suitable means The method involves initial high cost, but maintaince is very cheap.

18. Drip Irrigation :- It is also known as trickle irrigation. This method is suitable where the water scarcity and salt problem. This method was first introduced in Israel. Water is applied in the form of drops near the roots through a special outlet device called emitter or dipper . These emitters have drip nozzles to supply water drip by drip at a slow rate varying from about 2 lit/hr to 10 lit/hr. By the capillary action the water reach to the root vertically as well as laterally. Components of drip irrigation unit :- Control head Pipe network Emitter

19. Drip Irrigation Advantages Water saving is up to 40 to 60%. Enhance the plant growth & increases the crop yield. Very high irrigation efficiency. Improve efficiency of fertilizers. No soil erosion. Enhances the maturity of the crop. Disadvantages Initial cost of installation is high. Regular frequent maintenance is high. Only suitable for high value and widely spaced crops. Salinity hazard. High technical knowledge is required.

20. C. Sprinkler Irrigation :- In this method, water is applied to the land in the form of spray. It resembles a light rainfall in the form of a drizzle. It is also sometimes called overhead irrigation. The greatest advantage of sprinkler irrigation is its adaptabilities to use under conditions where surface irrigation methods are not efficient. This method is more useful under following situations :- The land can not be prepared for surface methods. Topography is irregular Slopes are excessive. S oil is erosive. Soil is excessively permeable or impermeable. Depth of soil is shallow over gravel or sand.

21. Sprinkler irrigation Advantages Erosion of soil is avoided or controlled. It is possible to apply water uniformly. There is no surface run-off. Labor cost is less. Damage of crop due to frost is reduced. It is a standby drainage pumping set. It can be used even with high water table. Seepage loss like earthen canal are eliminated. Disadvantages Wind may disturb or distort sprinkling pattern. A constant water supply is needed for commercial use of equipment. Water is to be clean and free from sand. Heavy soil with pore intake cannot be irrigated efficiently. Areas with higher temperature increase evaporation loss. It requires high electrical power.

22. Mobile Sprinkler Types : Raingun : A mobile machine with a big sprinkler. The speed of the machine determines the application rate. The sprinkler has a powerful jet system. Perrot irrigation machine are used for dust suppression in the rhine open cut brown coat mines.

23. Lateral Move System : A mobile long boom with many sprinklers attached to them. As the machine moves, it collects water from a canal into the sprinklers connected to the long boom.