# Geohydroology of a Reference Mediterranean Catchment (Cilento UNESCO Geopark, Southern Italy)
## 4 Discussion
The inorganic sediment or shallow landslides event exhibit a negative h index, \(\Delta\)Amin and \(\Delta\)Amax. This event differs from the organic sediment event characterized by a positive indexes. The snowmelt event exhibited h >0 (clockwise loop), \(\Delta\)Amin <0 and \(\Delta\)Amax >0. Specifically, in a forested catchment with no-evaporite bedrock, the Q-EC relationship was inverse: when the peak discharge occurred, the minimum EC value was recorded and vice versa. In this condition, the hysteretic loop would show a line during the rising phase, with a gentle negative slope until reaching the peak, after that, following a counter clockwise loop, it would reach the end point of the falling phase with h <0, \(\Delta\)Amax >0 and \(\Delta\)Amin <0. When pollution inputs occurred, the h index, \(\Delta\)Amax and \(\Delta\)Amin had the same values of the natural event; however, the dependent variable remained constant at the start of the event. For the snow melting case, h was <0, \(\Delta\)Amax >0 and \(\Delta\)Amin <0, the clock wise direction appeared and the dependent variable remained constant at the start of the event. Each type of event was associated with a well-specified pattern of the \(\Delta\)A variation with respect to the variable u(t). Plotting the resulted indexes of Table 4 in pairs, we found a clear isolated behavior for the compound event (Figure 14a), with parameter values that were quite different from the other events. In Figure 14b-d, we omitted the compound event to improve the readability of the graphs. Figure 14b,c shows a clear independent group of pollution events, but an overlap appeared between the snow and ordinary events that happened when the catchment was saturated and the sub-surface flow was the main runoff mechanism from the hollow and headwaters. A well-identified organic and inorganic sediment appears in the Figure 10c, plotting h versus \(\Delta\)Amax, while, in the graph of \(\Delta\)Amax versus \(\Delta\)Amin (Figure 14b), the values of the organic sediment are comparable with the pollution ones, excepting for the sign. Figure 14d does not give more information regarding the similarities among the estimated parameters h index vs. \(\Delta\)Amin. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Events** & **Event Type** & **Hindex** & \(\Delta\)**Amax** & \(\Delta\)**Amin** & **Dependent Variable** \\ \hline
16 February 14 & compound event & 0.47 & 0.12 & \(-\)0.000377 & decreases from the initial state \\
16 March 01 & ordinary & \(-\)0.0683 & 0.004231 & \(-\)0.006254 & decreases from the initial state \\
16 March 13 & sub-event & 0.1967 & 0.007489 & 0.001843 & decreases from the initial state \\
16 March 23 & ordinary & \(-\)0.0266 & 0.001851 & \(-\)0.007067 & decreases from the initial state \\
16 May 20 & ordinary & \(-\)0.0588 & 0.00179 & \(-\)0.002901 & decreases from the initial state \\
16 September 14 & organic sediment & 0.6345 & 0.018092 & 0.0021387 & constant from the initial state \\
16 September 22 & pollution & \(-\)0.0342 & 0.020928 & \(-\)0.004599 & constant from the initial state \\
16 September 19 & pollution & \(-\)0.1277 & 0.01615 & \(-\)0.006313 & constant from the initial state \\
17 January 15 & snow & 0.116 & 0.005079 & \(-\)0.006357 & decreases from the initial state \\
17 February 14 & snow & 0.0513 & 0.001395 & \(-\)0.000706 & constant from the initial state \\
17 November 6 & inorganic sediment & \(-\)0.2861 & \(-\)0.00029 & \(-\)0.025266 & constant from the initial state \\ \hline \end{tabular}
\end{table} 
Table 4: Hysteretic index results.