Appropriate Layouts of Micro-irrigation Laterals Laid on Uniformly Sloping Ground

Abstract:

The chosen of lateral layout is the basis of hydraulic design of microirrigation laterals. A simple and easily adaptable analytical approach was developed for the hydraulic design of microirrigation laterals laid on uniformly sloping grounds based on the appropriate layouts. Two indictors for comparing the emitter flow variation and inlet working pressure head from the paired layout and single downhill layout were proposed based on the analytical models of microirrigation laterals. By evaluating the effects of microirrigation laterals layouts on the emitter flow variation and working pressure head, the application condition for paired layout was suggested as the best manifold position is not less than 0.13. When the best manifold position is less than 0.13, the microirrigation lateral was proposed to use the single downhill layout in order to save the extra cost of material and installation from the paired layout. The design procedure for hydraulic design of microirrigation laterals was revised by considering the determination of appropriate layout. Two design cases covering various conditions indicated that the best manifold position criterion for determining the appropriate layout is more effective than the value of ground slope proposed by Keller method. The proposed approach could produce accurate results for practical purposes. This research could provide valuable information for improving the hydraulic design of microirrigation systems.