Evaluation the hydraulic performance of pressure compensating emitters

Abstract

Evaluating the effect of operating pressure on the water distribution uniformity in drip irrigation system is important in irrigation water management and could serve as the basis for optimizing water use efficiency and improving crop productivity. This study was to evaluate pressure compensating (PC) drip emitters to determine optimum operating conditions that achieve high water distribution uniformity, Average emitter discharge (Qvar), the coefficient of variation (Cv), the coefficient of uniformity (CU) and emission uniformity (EU) were evaluated under different levels of operating pressure. A 15 and 30 m length PE pipe with selected randomized emitter points on each lateral were considered for four different operating pressure OP (50, 100, 150 and 200 kPa). PC drip emitters used in this study had a design or manufacturing discharge rate of 4 L/h. Coefficient of Uniformity (CU) values for all OP with 30 m lateral length were above 90% and classified as excellent based on criteria for assessing drip irrigation system. Emission Uniformity (EU) values decreased as OP was reduced. Flow variations are essentially kept minimum as the OP is increased. As a result, the 200 kPa OP is recommended over the other OP considering the lateral length in the study. The results led to the following concluded points.

1- Discharges were increased by increasing operating pressure for both lateral lengths.

2- The high of water distribution uniformity was achieved at operating pressure of 200 kPa for both lateral lengths.

3- The values of water distribution uniformity for lateral length 30 m are higher than the values of lateral length 15 m at the same conditions of operating pressures.