Author(s): L. Castiglione; A. Cancelliere
Keywords: Water balance model; Soil moisture; Hydrological cycle; Climate change; Sicily basins
Abstract: Soil water balance models play a key role to quantitatively analyse hydrological cycle because they can provide insights on the formation of surface and groundwater resources. Besides, such models enable to quantify climate change impacts on the different components of the hydrological cycle. In the paper, a model originally proposed by Eagleson (1978), based on the soil moisture balance, has been applied to selected Sicilian basins (Italy). The adopted model enables to derive the probability distributions of terms of the annual water balance equation as a function of precipitation and other measurable physical variables of given basin. Since Eagleson’s model is a physically-based model, its implementation does not require any calibration phase, but only the characterization of input parameters related to climate, soil and vegetation of the analysed area. Therefore, an important work phase concerned the development of a methodology for the characterization of the different model parameters of the investigated area. Model validation has been carried out by comparing the empirical observed frequencies of water balance terms (precipitation, evapotranspiration and water yield at annual scale) with the corresponding CDF computed by the model. A general good agreement between distributions of observed data and model results has been obtained and this is particularly significant since observed streamflows have not been taken into account for characterizing the model parameters. Then an analysis of water yield modification under different hypotheses of climatic changes has been carried out, highlighting the adequacy of the model to evaluate the climatic changes effects on the hydrological processes, especially for ungauged basins.