Analysis and forecast of crop water demand in irrigation districts across the eastern part of the Ebro river basin (Catalonia, Spain): estimation of evapotranspiration through copernicus-based inputs

The agricultural sector is currently facing the uncertainty that accompanies climate change in terms of the availability of water resources, as well as the need to balance the water demand for agricultural irrigation with other uses in river basins. In Spain, irrigation districts (IDs) play a very important role in the management of water resources. The efficiency of ID water management involves finding an equilibrium between supply and demand. It is in relation to the latter where the uncertainty is greatest, because until now no tools have been available to characterize water demands with sufficient precision throughout irrigation campaigns. ID managers need precise information and the development of tools to support decision making in planning and water management. Therefore, this study aims to identify, compare and analyse the differences between the demands, allocations and consumptions of water for irrigation in different IDs of the eastern part of the Ebro basin during six consecutive growing seasons. In addition, projections of water demands up to 2100 are conducted using a dataset of six global climate models under different climate scenarios. Novel advances in remote sensing for evapotranspiration approaches using Copernicus-based inputs were used in this study. Large variabilities in water demands among IDs and in the adjustments between demands and allocations were observed, suggesting there is still much room for the improvement of water management. All climate projections have a very clear pattern indicating an upward trend in water demands until the end of the century.