Field Assessment of Irrigation System Performance

In the arid western United States, there is increasing competition for limited water supplies; and therefore, efficient irrigation is critical to sustaining agricultural productivity. This project was conducted to provide information to irrigators at the field level for improving irrigation system performance. Distribution uniformity (DU) was the primary measure for evaluating the performance of 385 irrigation systems. Over 80% of the evaluations resulted in recommendations for improvements, and in over 90% of the evaluations in which recommendations were made, irrigators applied at least one of the recommended remedies. Based on all systems evaluated, the mean DU was 64%, water cost averaged $0.11/m3 ($141/acre-ft), and the average annual application depth was 0.7 m (2.3 ft). Mean DU varied based on system type with 65% for agricultural sprinkler, 70% for microirrigation, 70% for furrow, and 49% for non-agricultural turf sprinklers. Irrigation systems that were retested following implementation of recommendations had an average improvement of 18% in DU.