Modelling historical and current irrigation water demand on the continental scale: Europe

摘要

Water abstractions for irrigation purposes are higher than for any otherpan-European water use sector and have a large influence on river runoffregimes. This modelling experiment assesses historic and current irrigationwater demands for different crops in five arc minute spatial resolution forpan-Europe. Two different modelling frameworks have been applied in thisstudy. First, soft-coupling the dynamic vegetation model LPJmL with the landuse model LandSHIFT leads to overestimations of national irrigation waterdemands, which are rather high in the southern Mediterranean countries. Thiscan be explained by unlimited water supply in the model structure and illegalor not gauged water abstractions in the reported data sets. The secondmodelling framework is WaterGAP3, which has an integrated conceptual cropspecific irrigation module. Irrigation water requirements as modelled withWaterGAP3 feature a more realistic representation of pan-European waterwithdrawals. However, in colder humid regions, irrigation water demands areoften underestimated. Additionally, a national database on crop-specificirrigated area and water withdrawal for all 42 countries within pan-Europehas been set up and integrated in both model frameworks.