Analysis of Irrigation Systems at a Sub-District Level

Recent years have shown how climate change is leading to an increase in drought events in the Po Valley, severely affecting irrigation and hence the agricultural sector. In this study, the agro-hydrological model IdrAgra was applied to a number of irrigation sub-districts in the Po valley, incorporating detailed land use and soil information and local agro-meteorological data. The sub-districts were selected among those with available data to represent the variability on irrigation system characteristics. The daily crop water requirements estimated by the model were compared with the water supplies for the period 2016-2022, including wet, average and dry years, enabling the assessment of the efficiency of the analysed irrigation systems. The initial analysis focused on seven sub-districts in the Lombardy region characterised by pressurised distribution networks and irrigation methods. In addition to the boundary conditions (e.g. presence of shallow groundwater table), important variables affecting the mismatch between the actual irrigation needs and the delivered irrigation volumes include the rigidity of the distribution system (e.g. rotational distribution) and the limitations of current field water application practices. The analyses were aimed at investigating the relative role of the different components of the irrigation system on the overall efficiency of water use. The results indicate that improved distribution and application practices can increase the efficiency of irrigation systems quite significantly in the context of the Po valley and supposedly in other irrigation contexts.