Influence of evapotranspiration formulation on long-term trends (1980-2022) of the Adige river basin hydrological water budget.

The Adige river basin (~11000 square kilometers) is the second longest in Italy and affects the population living in the Trentino-Alto Adige and Veneto region. It is an example of hydrological complex river basin because it includes high anthropization causing intensive and often conflicting water uses, presence of seasonal snow cover with runoff delayed from snow falling season to late Spring and Summer, glaciers, and irrigated areas, which are important for food production of the region.

In this work, we model the hydrological cycle of the Adige river basin over the period 1980-2022, investigating the effect of three evapotranspiration formulations on the long term trends of each hydrological compartments, i.e. soil moisture, groundwater storage, and river runoff. The modeling part is implemented by exploiting the potential of the open-source, semi-distributed, component-based hydrological modeling system GEOframe modeling system, which is applied at daily time-step and at a high spatial resolution (<5 km²).

The model, together with the different evapotranspiration formulations, has been validated against river runoff and satellite retrieved soil moisture data. Results, which have been analyzed also in the context of the 2022 drought which hit Northern Italy, show that increasing the complexity of the evapotranspiration formulation improved model performances for all the simulated hydrological components.