Design Service

It is necessary to design a suitable and economically viable system to deliver a predefined amount of water at the root zone of each plant at regular intervals. This is to ensure that the plants do not suffer from stress or strain of less and over watering. A totally customized, efficient, and long-life system ensures saving in water, early maturity, and a bountiful harvest,

Effective design should be reflected in its operation as far as flow variation is concerned. There should be minimum variation in the emission of drippers. Overall irrigation efficiency should be more than 90 %.

1. The design of drip irrigation differs from crop to crop, plot to plot, soil to soil, and climatic conditions. In general, the following steps are involved in the design of the MEIL drip irrigation system.
   1. Obtaining site information
   2. Calculation of water requirement
   3. Selection of drippers and calculation of irrigation time
   4. Selection and design of lateral
   5. Selection and design of sub-main line
   6. Selection and design of mainline
   7. Selection of pump

    

   1. Obtaining site information: Obtaining site information is a very important step in the design procedure. A complete and accurate survey with other field information is essential for designing an efficient irrigation system.
   2. Calculation of water requirement: While designing the MEIL drip irrigation system, the highest water required for the plant throughout its lifecycle is considered to calculate water requirement. While calculating peak water requirement, the peak rate of evapotranspiration is taken into consideration. For peak water requirements for various crops please refer to Annexure I. Please note that peak water requirements mentioned in Annexure-I are only for reference, actual water requirements may vary depending on soil type, agro-climatic conditions, crop variety, etc.
   3. Selection of drippers and calculation of irrigation time: Selection of drippers should be based on water requirement, soil type, water availability, electricity availability, etc. Drippers should be selected such that they should emit enough water to fulfill water requirements within a predefined time.
   4. Selection and design of lateral: The design of the lateral should be based on a maximum 7.5 – 10% discharge variation and up to 15% pressure variation. Laterals are available in various sizes of 12 mm, 16 mm, 20 mm etc. Calculate the average dripper spacing on laterals. e.g. if for any orchard crop having spacing 8 m x 8 m, we are providing 4 Kimneer drippers of 8 LPH per plant, then the average dripper spacing will be 8 m / 4 drippers, i.e. 2 Mtr. Then refer to Annexure-II, for average dripper spacing of 2 m, and for 8 LPH, 16 mm lateral can be laid up to 83 m and 12 mm lateral can be laid up to 49 m. For maximum lateral running length please refer to Annexure-II. Design the layout of the system considering maximum lateral running length so as to obtain higher uniformity.
   5. Selection and design of Submain: After finalizing drippers and laterals or in-lines, we have to decide the no of sections, for the entire area, so that the irrigation cycle can be completed in the available time for operation. The design of the submain for the particular section is based on both capacity and uniformity. The submain size should be large enough to deliver the required amount of water to irrigate the subsequent part of the field. Calculate the discharge for the respective section, and by referring to Annexure-II, decide the size of the submain. The size of the submain is optimized at a maximum 2 m head loss.
   6. Selection and design of mainline: After finalizing drippers, laterals/in-lines, and submain sizes and locations, we have to connect all the submains to the water source using the main line. The size of the mainline is decided by considering the quantity of water flowing through it. It’s very important to decide how many submains are to be operated at one time, and based on that the flow through the mainline is calculated and the size of the mainline is designed for that flow using Annexure-II.
   7. Selection of Pump: The size of the pump depends upon the flow of water required and the total pressure required at the pump to operate the irrigation system efficiently. While designing the system from drippers to mainline, we finalized the system flow (Q). The pump should have the capacity to deliver this flow. The required total head (H) of a pump is the sum of all following heads,
      1. Operating Pressure (considered 1 Kg/cm², i.e. 10 m),
      2. Head loss in laterals (considered 2 m),
      3. Head loss in submains (considered 2 m),
      4. Head loss in mainline,
      5. Head loss in fittings,
      6. Head loss in filters,
      7. Head loss in the venturi (if used very frequently),
      8. Head loss in NRV,
      9. Static head of the field,
      10. Pump suction and delivery head.

    

   Now our flow (discharge) and total head of the pump are finalized. We can calculate the approximate HP of pump using following formula,