Drip Irrigation Design Equations

In a drip irrigation system, a major design is the minimization of the discharge (or emitter flow) variation along a drip irrigation line, either a lateral or a submain. When the kinetic energy is considered to be small and neglected in a drip irrigation line, the pressure variation will be simply a linear combination of the friction drop and energy gain or loss due to slopes. Five pressure profiles were presented and considered. Procedures were developed to identify pressure profiles by landslope and total friction drop at the end of the line. Equations for designing lateral length (or submain) based on a given criterion were derived for all five pressure profiles. These equations cannot be solved directly, but solutions can be obtained using a trial and error technique on a pocket calculator or by using Newton's method of approximation in a computer program. The developed mathematical equations will be useful in the future development of computerized drip irrigation system design.