Assessment of hydraulic performance and water distribution uniformity in selected sprinklers under different layout of sprinkler irrigation systems

This study was aimed to determine the effects of sprinkler type, sprinkler layout, operating pressures and wind speed on water distribution uniformity of sprinkler irrigation system. The study was conducted in research station of Seed and Plant Improvement Institute (SPII) in Karaj, near the meteorological station during 2008-2009. The experimental design was randomized complete blocks design (RCBD) in factorial layout with different replications. The experimental treatments were combinations of 8 sprinklers (Farm-RC180, Jaleh 5, Komet 162, Luxor, VYR 155, Nelson24ΆF80 with one nozzle, Rain Bird 80EHD and Nelson F80,18Άwith two nozzle), 3 operation pressures (3, 4 and 5 atmosphere) and 4 wind speed range (0-5, 5-10, 10-15, 15-20 Km/hr) and 7 sprinkler layout (22.5*22.5, 25*20, 25*22.5, 25*25, 27.5*22.5, 27.5*25 and 30*25 meter). In order to determine the water distribution uniformity, a set of catch-cans were set around the individual sprinkler in 2.5*2.5 arrays. The volume of water in the catch-cans was measured after 1 hr operation for each treatment. The overlaping of sprinklers were simulated and water distribution uniformity for seven sprinkler layout were calculated. Results showed that the sprinkler type, sprinkler spacing, operating pressures and wind speed treatments had significant effect on water distribution uniformity (P΅Β 0.01). Sprinklers type were classified in five group from A to E. Sprinklers type of Komet 162 and Nelson F80 with two nozzle had high water distribution uniformity and classified in group A. Nelson F80 with one nozzle and VYR 155 types classified in second group. With increasing the operation pressures, water distribution uniformity were increased non-linearly. Water distribution uniformity was decreased when wind speed increased and was in an acceptable range, when wind speed was about 5 Km/hr. In general, the sprinkler type that classified in group A and B with the operation pressures of 4 to 5 kg/cm2 and 25*20 meters layout was recommended for overall agricultural conditions.