**3. Results**

#### *3.1. Water Balance*

The box plot (Figure 2) shows the distribution of the main water balance terms, their symmetry, and the presence of outliers. The outflow (Q) and the groundwater contribution (GS) have a higher variability than the other terms considering the distance between the quartiles. Moreover, runoff (RS) and the groundwater contribution (GS) highlight the presence of outliers.

**Figure 2.** Boxplot distribution of the main water balance terms.

The mean contribution of the groundwater source is around 41% of the entrance of the hydrological balance, with a minimum around −1% and a maximum around 79%. From the annual water balance analyses, we can highlight the negative contribution of the groundwater resource in 2008.

The tendency of percentage of groundwater (%Gs) is reported in Figure 3. The tendency was an increase starting in 2008 and a decrease starting in 2014.

**Figure 3.** Temporal trend of groundwater source percentage (red line) and the polyline (black line).
