Development and Test of a Decision Support System for Crisis Mitigation and Water Withdrawal Control in a Central Italian Irrigation District

The paper describes the characteristics and the functioning of a decision support system (DSS), which is useful for irrigation network managers. The DSS can be applied in the planning phase (P_Mode) to evaluate the sustainability of the cropping patterns (CPs) planned for the next season and in the management phase (M_Mode) to promptly identify and locate the occurrence of withdrawal anomalies during the irrigation season. The P_Mode relies on a crop water requirements model derived from FAO 56 (FAO56_M) using the planned CPs and the historical agrometeorological data as input. The output of the FAO56_M is statistically analysed and compared with the expected water availability, making it possible to assess the probability that the irrigation network may enter a crisis. In the M_Mode, the DSS compares the real-time FAO56_M estimates with the water withdrawals measured by a smart water meter system. The case study concerns an irrigation district (ID10) of about 320 irrigated hectares in the central Italy. The district is divided into 23 delivery points (DPs), each equipped with a smart water meter. The 2013–2020 data on crops, agrometeorological variables and seasonal water consumptions measured in ID10 allowed the calibration of the FA056_M model, which showed satisfactory accuracy (Mean Absolute Percentage Error ≈ 13%). The DSS was tested between 2021 and 2023. In the P_Mode, the predicted consumption (with a 10-year return period) was always lower than the presumed availability, confirming the sustainability of the planned CPs. In the M_Mode, the use of the DSS proved effective, allowing several anomalies in withdrawals to be identified. The leading causes were inaccuracies in the declared CPs and configurations of the areas served by each DP.