A theoretical economic model of the demand for irrigation water

•This paper uses a damage control approach to model the derived demand for irrigation water in field crops in historically rain-fed agriculture regions. Irrigation of field crops has been hypothesized to be a potential adaptation strategy in the face of projections of climate change.•This paper contributes an economic method to determine the irrigation water demand by taking into account water from precipitation, potential crop yield, input prices, crop price and farmers' profit.•Compared with an engineering method based on estimated crop water requirements for potential crop yield, the optimal derived demand for irrigation water from an economic method can result in benefits for farmers as well as enhanced conservation of water resources.