Effects of climatic and hydraulic parameters on water distribution uniformity coefficient in sprinkler irrigation system in Omidieh district

In order to study the effects of wind velocity, operating pressure, various sprinkler layouts and spacing on water distribution uniformity in sprinkler irrigation system, a research project was conducted under three different wind velocities (0 - 5, 5 - 7, and > 7 m/s), using three operating pressures (35, 40 and 45m), three spacing on the lateral pipeline (15, 18 and 21m) and three different layouts (square, rectangular and triangular). Simulation experiments were conducted to estimate the water distribution uniformity. The results indicated that the distribution uniformity coefficient decreased with increasing of wind velocity. With the increase of wind velocity up to 7 m/s, the decrease of uniformity coefficient was not significant (the coefficient was reduced by 20% in the range of wind velocity applied). The highest water distribution uniformity coefficientoccurred for 15×15 m spacing while the lowest value was achieved for the spacing of 21×21 m and sprinkler spacing to spraying diameter of 0.5×0.5. With the increase of sprinklers spacing to the spraying diameter, uniformity coefficient is reduced, especially at higher wind velocities, therefore at higher wind velocities, it is recommended to reduce the sprinkler spacing to spraying diameter ratio and use square arrangement in order to achieve an acceptable uniformity.