# Hydrological Analysis of Extreme Rain Events in a Medium-Sized Basin
## 3 Results
The Nash-Sutcliffe coefficient was satisfactory for the sub-basins W1460, W900, and W1030 of the 7-15 April 2013 rain event, good for W790 and W800, and very good for W1020. For the 30 April-7 May 2017 precipitation event, the index was satisfactory to good for the sub-basins W1030 and W1020, respectively, whereas it was very good for the rest of the gauged sub-watershersds. Noticing Table 13, concerning the HBV-light hydrological model, the FC parameter was higher in the rural sub-basins and fairly smaller in the urban and semi-urban sub-basins, as also mentioned in the events that had high precipitation intensity. Dissimilarities were mentioned in the fitted parameters of the soil moisture routine, as regards the rural sub-basins with quite urbanized areas. Specifically, FC was notably higher in W800 than in W900. Additionally, LP was smaller in W800 in comparison with W900, but also higher than the corresponding values which calibrated the events with high precipitation intensity; in contrast, the higher values of LP in W900 were lower than the respective ones of the high rainfall intensity events. Apart from these, the BETA values were remarkably higher in W900 for the forests and croplands zones, but not in the urban zone in which the calibrated values were similar in both sub-basins. Comparing the BETA parameter in the semi-urban and urban sub-basin, it was particularly higher in the semi-urban one. The PERC rate was greater in the most rural sub-basins and lower in the semi-urban and urban ones. However, W800 and W900, both having similar urbanized regions, performed well with a different maximum percolation rate. The UZL value did not indicate any particular trend in the sub-basins, except for being relatively small. The K0 recession coefficient was higher than K2, which was also higher than K1, in all the sub-basins apart from the semi-urban one; in the latter sub-watershed, the K1 coefficient fit better being greater than K0. The Nash-Sutcliffe index was good for the sub-basins W1460, W790, and W1030 of the 7-15  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & W1460 & W790 & W800 & W900 & W1030 & W1020 \\ \hline \multicolumn{1}{c}{\(TT\) (\({}^{\circ}\)C)} & \(-0.5\) & \(-0.5\) & \(-0.5\) & \(-0.5\) & \(0\) & \(0\) \\ \multicolumn{1}{c}{\(C\)_MAX_ (mm/h \({}^{\circ}\)C)} & 0.15 & 0.15 & 0.15 & 0.15 & 0.15 \\ \multicolumn{1}{c}{\(SP\)} & 1 & 1 & 1 & 1 & 1 & 1 \\ \multicolumn{1}{c}{\(SFCF\)} & 0.7 & 0.7 & 0.9 & 0.9 & 1 & 1 \\ \multicolumn{1}{c}{\(CFR\)} & 0.05 & 0.05 & 0.05 & 0.05 & 0.05 & 0.05 \\ \multicolumn{1}{c}{\(C\)_WH_} & 0.1 & 0.1 & 0.1 & 0.1 & 0.1 & 0.1 \\ \multicolumn{1}{c}{\(F\)_(mm)_} & 495 & 495 & 495 & 120 & 120 & 100 \\ \multicolumn{1}{c}{\(F\)_(\(\!\)\(\!\)\(\!\)\(\!\)\(\!\!\)\(\!\!\)\(\!\!\!\)\(  
The two events of 26-30 June 2010 and 22-25 June 2017 exhibited wet AMC at the sub-basin W1460, normal AMC at W790, W800, and W900, and dry AMC at the urban (W1030) and semi-urban (W1020) sub-basins. The detailed values of the parameter calibration procedure that produced the optimum Nash-Sutcliffe indices at the exit of the studied sub-basins, per hydrological model, are displayed in Tables 14 and 15. Examining Table 14, for the HEC-HMS hydrological model, the selected values of the ratio \(R/(T_{c}+R)\), in comparison with the reference values of Table 4, increased by 2%, 5.5%, 31.8%, and 14.7% in the sub-basins W1460, W800, W1030 and W1020, respectively. In contrast, in the sub-basins W790 and W900, these were decreased by 7.5% and 6.5%. Especially for the sub-basin W1030, an adjustment factor equal to 0.7 was applied at the Carter formula calculating the \(T_{c}\), to manage the time of occurrence of modeled flow to be closer to the observed. Calibrating the \(CN\), the chosen values displayed a decrease to all the sub-watersheds in relation to the reference values.