Evaluation of hydraulic calculation methods of micro-irrigation lateral line in level and uphill slope

Irrigation projects that are hydraulically well-dimensioned provide a good distribution uniformity coefficient and, consequently, high irrigation efficiency. This research aimed to evaluate and compare the method's performance using the energy gradient line (EGL) concept and the modified forward step method (FSM), in the design of micro-irrigation lateral lines, under different scenarios. To apply the models, the following sources of variation were used: (i) six emitter flow variations (from 0.04 to 0.19 with increments of 0.03); (ii) two slope gradient line (so= 0% and -3%); (iii) two equivalent emitter connector lengths (le = 0m and 0.5m). There was no difference between the methods based on the magnitudes of the response variables, which presented similar values for maximum operating pressure head and total pressure loss, regardless of the combination of the factors considered in this study. In turn, the sources of variation affected the results when each hydraulic calculation method was fixed. The results confirmed that the point of occurrence of the mean pressure, at half the maximum length of the lateral micro-irrigation line, provides greater accuracy in the maximum pressure estimated by the EGL method. Thus, the EGL is very accurate when compared to the modified FSM, and as a result, can also be recommended for designing single laterals for micro-irrigation.