Explicit Hydraulic Design of Microirrigation Submain Units with Tapered Manifold and Laterals

Abstract

The optimum hydraulic design problem for microirrigation submain units of specified dimensions is solved analytically. New algebraic equations were derived to calculate explicitly the optimum values of the design variables. The design variables are the lengths of two given pipe sizes for the laterals as well as the appropriate lengths of the available pipe sizes for the manifold. Tapered laterals and manifold are selected in such a way that the sum of the costs of the laterals and the manifold is minimized, while the hydraulic design criterion is ensured. The case of a single-diameter lateral with tapered manifold pipeline is also examined. The design procedure can be also applied in sprinkle irrigation tapered laterals. The explicit optimum design solution is demonstrated in two cases studied.