A high number of papers and studies have shown that the modernization of irrigation systems and the increased efficiency in the use of irrigation water do not guarantee real water savings due to phenomena such as the reduction of water returns into rivers and aquifers and the Jevons hydrological paradox. However, the effects of modernization of irrigation systems on the agricultural diffuse pollution is not so clear: water returns reduce but, on the contrary, the concentration of agricultural pollutans increase. I would grate all kind of papers and studies around these issues