The hydraulic design of microirrigation systems requires particular attention because the pressure at the emitters is low, often below 130 kPa and sometimes below 60 kPa. Relatively small friction head losses and variations in elevation, which would be acceptable in sprinkler irrigation, cause high relative variations in the operating pressure of the emitters.
The principles for hydraulic design are well presented in manuals [11, 124, 127] and are not presented here. In recent developments with microirrigation modeling [133-136], the hydraulic computations are combined with calculations of the expected uniformity indicators.
System pressure control, mainly pressure regulators, often must be used to maintain acceptable pressures. The type and position of control will influence the system layout and the length and diameters of submains and manifolds. For large systems, controls may be required at submain inlets. When the system is irrigating sloping land, pressure regulators may be required at manifold inlets. When laterals are along a slope or are very long, the pressure regulation may be required for each emitter (pressure-compensating emitters).
Was this article helpful?