To avoid the rebound effect in irrigation modernization, it is necessary that the net efficiency increase of the system be accompanied by a sufficient reduction in water supply so that water consumption, the product of the new (increased) efficiency and the new (reduced) supply, is maintained or decreased.

 

In order to incorporate all aspects involved in the conversion processes from extracted water to consumed water (evapotranspiration), a rational methodology is established to evaluate the Consumption Use Index (ICU) before and after modernization. In addition to the traditional coefficients (Application Efficiency and Distribution Efficiency), it introduces three new indices related to consumption associated with leakage, non beneficial consumption at plots, and crop water stress.

 

This allows, among other objectives, to estimate the changes in consumption for given changes in water allowance, and to conclude that in modernizations from surface irrigation to sprinkler irrigation the reduction in allowance must be in the order of 22%, and in the order of 30% in the case of change to drip irrigation, so that consumption does not increase.