FIELD ASSESSMENT OF PERFORMANCE WATER LOSSES OF CENTER PIVOT IRRIGATION SYSTEMS UNDER ARID CLIMATE CONDITIONS

Abstract

the centre pivot system is one of the most appropriate sprinkler systems for arid or semi-arid areas where a great deal of irrigating water. The system is used widely in Saudi Arabia, and there were more than 20,000 centre pivot systems in the country. To know the reality of water application, water losses and distribution uniformity by this type of irrigation system in this country, a study was conducted in Riyadh region to evaluate 8 centres pivot systems with different ages and made of various companies and consisted of the different number of towers ranged from 4 to 10. The results showed that most of the centre pivot systems gave low distribution uniformity during water application in the irrigated areas. The values of coefficient of uniformity (Cu) were ranged between 69.2% and 89.2%, while the values of the distribution of uniformity of low quarter (Du) were between 54.1% and 81.6%, and water losses from these systems were ranged between 7.83% and 13.57%. The study also investigated the effect of main factors on water distribution and water losses in arid areas by developing a statistical model in order to determine the relationship between the losses and the factors affecting them under operating field conditions. The results of this study could assist the farmers to identify the irrigation and how to improve the system performance and the developed regression model could provide valuable information for the water application and water losses with centre pivot irrigation system in the region facing aridity and water scarcity.