Corrections to Global Gridded Irrigation Efficiency Datasets in Groundwater-Dependent Croplands

Irrigation efficiency improvements have been recognized as a key strategy to increase the 'crop per drop' ratio of water allocated to the agricultural sector, yet at the same time, there is a lack of comprehensive irrigation efficiency datasets at the global scale. Most of the currently available data are either outdated, or fail to account for the groundwater dimension of this indicator. Aiming to determine multiple dimensions of irrigation efficiency within an intertwined surface water and groundwater irrigation scheme, we try to modify the currently available datasets. Here, we provide a global dynamic irrigation efficiency dataset at a 5×5 arc-minute resolution, corrected for groundwater contributions in each grid cell. We add a new dynamic layer to the available irrigation efficiency datasets, called groundwater irrigation efficiency, which varies across the globe and throughout the year based on multiple factors. These factors include pumping system properties, groundwater table, surface water and irrigation water demand, and climatic and environmental conditions. Our work improves the understanding of  the role of groundwater contributions in supplying irrigation water and helps to minimize  biases in the estimated irrigation efficiencies, consequently leading to more accurate evaluations  of agro-hydrological flows.

Keywords: irrigation efficiency, groundwater-led irrigation, pumping energy, groundwater scarcity.