Assimilating Farmers’ Behaviour in the Development of an ET-Based Irrigation Water-Accounting Model

Reliable accounting of agricultural water use is critical for sustainable resource management, particularly in regions where the operation of on-farm private wells account for the largest share of groundwater exploitation. While in-situ groundwater metering entails technical, economic and political difficulties, accurate model-based estimation of irrigation water abstractions remains critical. In this context, the current research aims at developing a prompt water balance model in order to quantify on-farm irrigation water abstraction. In our approach, we assume that irrigation water uses besides being crop-specific are influenced by farmers’ behavioural variables seldom considered in water balance models. To this end, a controlled survey experiment has been carried out on an ad-hoc sample of irrigators across the Apulian region, southern Italy. Eventually, an irrigation water-accounting model incorporating farmers’ behaviour, named IRMAT (IRrigation MAnagement Tool) has been described and implemented. Findings show that IRMAT has the potential to be a useful tool to help farmers compiling their annual water abstraction audit often requested by water authorities or to develop farm-scale water balance predictions under different cropping patterns or irrigation developments. Lessons learnt for further modelling for district and basin scale agricultural water balance are pointed out.