Investigation of Infrastructural and Management Actions to Increase the Resilience of Existing Pressurized Irrigation Networks

In recent decades, on-demand irrigation systems have been promoted to increase water use efficiency. This study focused on the assessment of two traditional rotational pressurized irrigation systems with a central pumping station in the Foggia Province (Italy). Irrigation system A has an area of 564 ha with 319 pipelines and 251 hydrants, and irrigation system B has an area of 445 ha with 280 pipelines and 214 hydrants. The nominal discharge of each hydrant is 10 l/s. In each of the two irrigation systems, 1000 different operation scenarios were investigated using the COPAM model. To evaluate the performance of the systems, the indices of Relative Pressure Deficit (RPD) and Reliability (RI) were used. Results showed that the systems are quite flexible and allow the required flow rate to be increased by 1.6 times the peak period flow rate, if necessary. With such increased discharges, it is impossible to guarantee the RPD (RPD >= 0) and RI (RI = 1) indices in 47% of the hydrants in the irrigation system A and in 36.9% of the hydrants in the irrigation system B. An updated methodology for optimizing the pipe diameters starting from the current situation was also implemented. Around 23% of pipelines in each system were changed with such methodology. After the new optimization, the number of unsatisfied hydrants in both systems decreased by 94.1% (from 118 to 7 hydrants) and 82.3% (from 79 to 14 hydrants), respectively. Thus, with this methodology, the irrigation system performance can be improved.