Guidelines for Evaluation of Center pivot Irrigation System Performance (Technical note)

Evaluation of any irrigation system consists of analyzing the measurable performance of the system in real conditions as well as during the normal operation of the farm. Irrigation evaluation is a management tool that allows the system manager to make the best use of what is available. Unfortunately, in most regions of Iran, after the implementation of irrigation systems their performance is not controlled or supervised. Also, during the operation of the system, the efficiency is not monitored nor analyzed either. Furthermore, the importance of irrigation system evaluation is not clarified to the users in our country. Despite the numerous research that has been conducted on the evaluation of center pivot irrigation system performance by domestic and foreign scholars, due to the complexity of existing evaluation methods, most farmers are not able to use them. Thus, in this paper, we have aimed to provide concise and simplified instructions for evaluating center pivot irrigation systems in order to help farmers in using them more readily. For evaluation of an irrigation system, the use of indexes such as water distribution uniformity, potential output and actual output for irrigation are recommended. Water distribution uniformity is an indicator of the water distribution problems in an irrigation system. The potential output of irrigation index describes the system performance under the current circumstances. Actual output of irrigation is an index that identifies the irrigation management, however it does not show the accuracy of the irrigation system design. According to the review conducted from academic resources, for a center pivot irrigation system, with a water distribution uniformity value of less than 76%, the irrigation potential and actual outputs value of less than 80% and 75%, respectively, are not suitable.