Potential command areas of irrigation dams

Irrigation will play a vital role in meeting future food demand. Irrigation reservoirs currently account for 40% of global surface water used for irrigation and play a critical role in agricultural production by providing water to overcome scarcity, buffering  against climatic variability, and enabling enhanced yields and multi-cropping. Yet while there has been ongoing establishment of dams for irrigation across the globe, there is little understanding of the extent to which irrigation has actually expanded within their potential command areas (PCA) (i.e., [the area that can be irrigated using water from a particular irrigation source]) and whether some irrigation dams have not yet realized the full extent of irrigated agriculture that they can potentially support. To assess this, we combine georeferenced information on recently established dams (year 2000 onward) (including dam height and reservoir capacity) with elevation data to first delineate the extent of each recent major irrigation reservoir globally (N=441) and estimate the extent of each dam’s PCA, based on pumping capacities for multiple classes of irrigation pumps.