Improving emitter outflow uniformity within a drip irrigation subunit

Comparison between traditional end-closed drip irrigation laterals, connected laterals at their ends using a second downstream manifold, and closed circuits looped laterals is performed to analyze the hydraulics of the distribution systems and to assess outflow uniformity. Detailed solutions for the three alternatives are achieved using the Engineering Equation Solver (EES). This software can solve a set of nonlinear equations simultaneously. A drip irrigation subunit of 250 m x 60 m is analyzed using EES to determine emitters’ pressures and discharges for 66 runs. Some runs cover emitter characteristics, pumping heads, manifold slopes, lateral slopes, diameters of the second downstream manifold, and other runs cover the case when few laterals are closed at their inlets. Christiansen uniformity coefficient and the relative flow difference are calculated for all cases to compare the distribution uniformity of the three alternatives. The results show that connected laterals generally achieve higher uniformity except in very few cases related to the land topography. The looped lateral alternative is equivalent to the traditional end-closed alternative giving the same coefficient of flow uniformity. © 2020, Cairo University. All rights reserved.