## 3 Results
### Hydrological Evaluation of Discharge Simulation Using Two SPPs
#### 3.3.1 Event of 20 November 2014  
This event represents a torrential flood; since the flood was generated by extreme precipitation spread over more than 15 days, it is the most intense event in the data set. The maximum flow reached was (123, 75 m\({}^{3}\)/s). However, the soils were saturated, resulting in high permeability and an increase in the runoff coefficient of the watershed.  
The results of the calibration of the 3B42V7 and IMERG V05 rainfall data with the observed flow illustrated in the hydrographs of the Figure 2, show that the simulated flow curves were globally well reproduced for both products at the flood rise and the recession part, although the peaks flow were not reached by both products.  
Based on the results the 3B42V7 calibration is satisfactory, as this product has a good capacity to record the high precipitation intensity during rainy episodes.  
Furthermore, the IMERG V05 product does not have the ability to capture heavy precipitation; this is well demonstrated in the calibration results. The evaluation criteria  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Id** & **Events** & **Calculated CN** & **Nash-Sutcliffe** & **RMSE** \\ \hline \multirow{8}{*}{**Validation**} & \multirow{3}{*}{3B42V7} & **20 November 2014** & 60.39 & 0.58 & 0.6 \\  & & **21 March 2016** & 56.98 & 0.64 & 0.6 \\  & precipitation & 3 May 2016 & 59.03 & 0.83 & 0.4 \\  & & **16 December 2016** & 55.83 & 0.51 & 0.7 \\ \cline{2-6}  & \multirow{3}{*}{3B42V7} & **20 November 2014** & 59.2 & 0.52 & 0.7 \\  & & **21 March 2016** & 65.9 & 0.56 & 0.7 \\  & & **3 May 2016** & 63.05 & 0.61 & 0.6 \\  & & **16 December 2016** & 60.18 & 0.63 & 0.6 \\ \hline \multirow{8}{*}{**IMERGV5**} & \multirow{3}{*}{3B42V7} & **20 November 2014** & 39.5 & 0.71 & 0.6 \\  & & **21 March 2016** & 50.5 & 0.74 & 0.5 \\ \cline{1-1}  & & **3 May 2016** & 47 & 0.73 & 0.5 \\ \cline{1-1}  & & **16 December 2016** & 49 & 0.57 & 0.7 \\ \cline{1-1} \cline{2-6}  & \multirow{3}{*}{**Mean**} & & **0.64** & \\ \hline \hline \end{tabular}
\end{table}
Table 6: Episodes validation results.  
Figure 2: Calibration of the episode 20 November 2014, using 3B42V7 and IMERG V05 rainfall products and observed runoff data as input.  
are suitable RMSE = 0.5 for both products and a Nash of 79.20% and 70.10% for 3B42V7 and IMERG V05, respectively.  
The validation hydrographs results in (Figure 3) were well reproduced for both products. The rise and the recession curves were well reproduced for 3B42V7, noting a slight underestimation of precipitation, but in general, this product well estimates heavy precipitation events. The IMERG V05 was not able to reproduce the validation hydrograph of this event. The rising curve was underestimated in the first pick as it represents the heavier precipitation during this event, and the other two picks were underestimated, the peak flow was not reached. This is because of the inability of this product to properly estimate the heavy precipitation.  
The evaluation criteria are acceptable with an RMSE of 0.7 for both products, and a Nash of 52.20% and 66.50%, respectively.