Irrigation efficiency and water saving: scale and rebound effects

Abstract

Improving on-farm irrigation efficiency have many benefits, however, it may mislead policies aiming to increase the availability of water at watershed scale. The effect of improving on-farm efficiency on global efficiency is highly dependent on the hydraulic arrangement of the irrigation units and the degree of reutilization of return flows. Moreover, an improvement of irrigation efficiency may entail an increase of evapotranspiration, contributing to the watershed water depletion. Water policies must take these issues into account.