## 4 Results and Discussion
### Impact of a Proposed Redarge Dam on the Infiltration of Water on the Tata Alluvial Aquifer
#### 4.3.3. Geoelectrical Cross-Sections  
* Section 1 shows alternating resistive and conductive layers (Figure 10). The alluvium formations above the piezometric level (PL) are resistant. Those below the PL have low resistivity whose origin can be due to the impact of water or, possibly, the existence of clayey elements in this layer. The resistant bedrock, not reached by the mechanical borehole S3, is estimated at a depth of 41, 50, and 52 m at TA5, TA3, and TA4 VESs. This geo-electrical section shows this alluvial aquifer's significant potential (average of 50 m). * Section 2 shows a less resistant cover above the PL than Section 1. It, possibly, corresponds to limestone and lacustrine clay. The top of this resistant layer deepens slightly from SW to NE. * Section 3 shows a slight dip of the bedrock from SW to NE, reaching a depth of about 57 m at TA14 VES. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Layer**} & **Layer** & **Resistivity** & \multirow{2}{*}{**Thickness (m)**} & **Roo Depth of the** \\  & **Designation** & **(Ohm.m)** & & **Layer (m)** \\ \hline
1 & & 1682.75 & 2.08 & 0 \\
2 & & 340.55 & 2 & \(-\)2.08 \\
3 & Ro & 893.41 & 2 & \(-\)4.08 \\
4 & & 172.15 & 4 & \(-\)6.08 \\
5 & & 1389.47 & 4 & \(-\)10.08 \\ \hline
6 & Cp & 29.02 & 36 & \(-\)14.08 \\ \hline
7 & Rs & 1195.41 & inf. & \(-\)50.08 \\ \hline \hline \end{tabular} Standard deviation= 3.166472\({}^{-2}\), Max Relative Error = 6.83%, Number of iterations = 10.  
\end{table} 
Table 3: Model optimization results of TA3 VES. Figure 9: Electrical survey family graphics. 4.3.4. Modeling the Infiltrated Water Volumes by the Effect of the Future Recharge Dam  
The alluvial formations that will be subject to artificial recharge by the dam correspond to the alluvial deposits located just upstream of the dam, more precisely the areas that will be occupied by water when it is accumulated within the dam, and those located downstream of it when the water is released through the dam's discharge pipe. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Section** & **VES** & **Thickness of the Alluvium (m)** & **Average Thickness (m)** \\ \hline \multirow{4}{*}{1} & TA1 & 41 & \multirow{4}{*}{46} \\  & TA 2 & 44 & \\  & TA 3/S3 & 50 & 46 \\  & TA 4 & 52 & \\ \cline{1-1}  & TA 5 & 42 & \\ \hline \multirow{4}{*}{2} & TA 6/S2 & 48 & \multirow{4}{*}{42} \\  & TA 7 & 48 & \\ \cline{1-1}  & TA 8 & 44 & \\ \cline{1-1}  & TA 9 & 38 & \\ \cline{1-1}  & TA 10 & 32 & \\ \hline \multirow{4}{*}{3} & TA 11 & 26 & \multirow{4}{*}{42} \\  & TA 12/S1 & 41 & \\ \cline{1-1}  & TA 13 & 35 & \\ \cline{1-1}  & TA 14 & 57 & \\ \cline{1-1}  & TA 15 & 50 & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Thickness of the alluvium according to the vertical electrical soundings. Figure 10: Geo-electrical sections deduced from the interpretation of the VES. The horizontal permeability measured in the alluvial deposits of the Wadi Tata is 10\({}^{-3}\) m/s, corresponding to an infiltration rate of 1.5 m/day. Moreover, the analysis of the results obtained by the Souss Hydraulic Basin Agency on the releases from the Aoulouz dam for the recharge of the Souss river basin provides an infiltration rate of about 1 m/d. Given the similarity between the physical characteristics of the alluvial deposits of the Tata and Souss rivers and the correspondence of the calculated permeability values in both areas, the adopted infiltration rate is 1 m/day = 0.04 m/h. To evaluate the effect of the planned dam on infiltration in the aquifer, the flood recorded at the Kasba Zolite station on 10 November 1988 was chosen. This flood is characterized by a very sharp and pointed hydrograph, which shows a rise time of 3 h with a peak flow of 277 m\({}^{3}\)/s, and the recession, which is generally slower, lasted several hours. The flood had a duration of 31 h, an average flow rate of 46.6 m\({}^{3}\)/s, and a total water volume of 5.2 million m\({}^{3}\).