Assessing climate change impacts on an irrigation scheme by hydrological modelling

The aim of this work is to evaluate the effects of climate change on the water balance of a maize crop in an irrigation district of Southern Italy ("Destra Sele", Campania Region, 22.645 ha). Two climate scenarios were considered, "past" (1961-1990) and "future" (2021-2050), the latter constructed applying statistical downscaling to GCMs scenarios. For each climate scenario and for each soil unit (25 units in the whole area), an indicator of the soil water regimes (crop water stress index CWSI) was calculated by means of the hydrological model SWAP, applying different irrigation strategies. The soil hydraulic properties were derived by means of tested and validated pedo-transfer functions (PTF; HYPRES). Crop-specific input data and model parameters were derived from local field experiments where the SWAP model was calibrated and validated. The results show an increase of CWSI in the future climate scenario, with some spatial patterns strongly influenced by the soils characteristics.