**3. Results**

The average annual values of the water balance for the whole simulation period are depicted in Figure 2, while monthly water balance components are reported in Table 2. Interannual variability showed that precipitations were concentrated in winter months, while in summer months the average precipitation remained quite stable due to the influence of the gauge stations in the Daunia mountains which have a maximum altitude of 1000 m.


1 All values in mm.

**Figure 2.** Schematic representation of average annual values of water balance. All units in mm.

The results showed that evapotranspiration was the predominant water balance component, with 598.39 mm year<sup>−</sup>1, accounting for approximately 85.5% of the annual precipitation (699.5 mm), followed by surface runoff (42.97 mm year<sup>−</sup>1, representing about 6.1% of the annual precipitation) and water yield (water discharged in the channels, 43.4 mm year<sup>−</sup>1). The potential evapotranspiration component was equal to 1047.33 mm year −1, while the average precipitation was equal to 699.5 mm year<sup>−</sup>1. The average annual outflow for the whole simulation period was 0.44 m<sup>3</sup> s–1, in line with the values registered for conterminous river basins in the Apulia region [14], confirming the overall reliability of the model.
