Investigation of Design Vulnerability of Pressurized Irrigation Systems under Climate Change Conditions (Case Study of Pressurized Systems implemented in Sonqor)

The main objective of this study was to investigate the vulnerability of pressurized irrigation systems performed in the Sonqor region in terms of climate change during the period 2011-2030 based on different scenarios (A1B, A2 and B1) compared to the base period using the LARS-WG sub-scale model. In this study, the reference evapotranspiration and irrigation requirement under climate change scenarios for the present cropping pattern were calculated and then the performance of irrigation systems and defined indices (such as pressure and flow distribution adequacy) were evaluated for further investigation. Based on the results obtained, crop evapotranspiration in all three scenarios A1B, A2 and B1 will increase by 9.53, 9.6 and 9.54%, respectively. The average flow amount of the studied systems will change from 6.8 lit s-1 to 9.74 lit s-1 in the future period. Average values of water velocity, are considered to increase 19.6, 20.6 and 19.6 percent in three scenarios A1B, A2 and B1, respectively. In the studied systems, the average values of pressure drop per 100 meters were 1, 19.1, 21.1, and 19.1 meters in the base period and three scenarios (A1B, A2 and B2), respectively, so there is no need to change the sprinkler or pressure adjustment at the beginning of the line. The results of irrigation area stability index, pressure and flow adequacy index showed that the values of this index would be less than 100% in the future in all fields studied.