## 3 Results and Discussion
### Microbiological Indicators of Water Quality  
The analysis of the microbiological quality of the water, evaluated through the enumeration of groups of indicators in the main inlets and outlets of the LVID (Figure 2 and Table 2), shows the effect of the different agricultural activities conducted here on the quality of the water at its outlet. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Sampling Site**} & \multirow{2}{*}{\begin{tabular}{c} **pH** \\ **(6.5–8.4)*** \\ \end{tabular} } & **Cl, mg/L** & **TDS, ppm** & **SDO, \%** & **EC, \#S/cm** & **SAR** \\  & **(70)*** & **(640)*** & **(1000)*** & **(8)*** \\ \hline \begin{tabular}{c} LVID--Inlets \\ upstream \\ \end{tabular} & 7.8 \(\pm\) 0.5 & 69.4 \(\pm\) 15.7 & 444 \(\pm\) 47 & 92.7 \(\pm\) 15.0 & 666 \(\pm\) 117 & 1.4 \(\pm\) 0.2 \\ \hline \begin{tabular}{c} Block Inlet \\ \end{tabular} & 6.9 \(\pm\) 1.1 & 39.1 \(\pm\) 14.1 & 179 \(\pm\) 7 & 97.1 \(\pm\) 4.8 & 285 \(\pm\) 32 & 1.8 \(\pm\) 0.1 \\ \hline \begin{tabular}{c} Paddies' Inlet \\ \end{tabular} & 7.3 \(\pm\) 0.2 & 41.5 \(\pm\) 15.0 & 428 \(\pm\) 137 & 91.1 \(\pm\) 14.3 & 651 \(\pm\) 211 & 1.8 \(\pm\) 0.2 \\ \hline \begin{tabular}{c} Paddies--Soil \\ Groundwater \\ \end{tabular} & 7.2 \(\pm\) 0.1 & 71.1 \(\pm\) 10.1 & 550 \(\pm\) 115 & 48.5 \(\pm\) 26.3 & 827 \(\pm\) 26 & 2.2 \(\pm\) 0.3 \\ \hline \begin{tabular}{c} Paddies-- \\ groundwater \\ \end{tabular} & 7.0 \(\pm\) 0.3 & 143.0 \(\pm\) 11.3 & 870 \(\pm\) 217 & 53.9 \(\pm\) 29.1 & 1336 \(\pm\) 336 & 1.9 \(\pm\) 0.1 \\ \hline \begin{tabular}{c} Paddies-- \\ water \\ \end{tabular} & 7.2 \(\pm\) 0.3 & 62.0 \(\pm\) 16.9 & 827 \(\pm\) 299 & 56.2 \(\pm\) 19.1 & 1327 \(\pm\) 518 & 1.9 \(\pm\) 0.1 \\ \hline \begin{tabular}{c} Paddies' Outlet \\ \end{tabular} & 7.4 \(\pm\) 0.1 & 45.2 \(\pm\) 15.1 & 377 \(\pm\) 100 & 71.7 \(\pm\) 6.0 & 582 \(\pm\) 153 & 1.8 \(\pm\) 0.2 \\ \hline \begin{tabular}{c} Block II Outlet \\ \end{tabular} & 7.3 \(\pm\) 0.3 & 259.3 \(\pm\) 112.4 & 670 \(\pm\) 267 & 76.3 \(\pm\) 13.6 & 1087 \(\pm\) 387 & 6.3 \(\pm\) 2.2 \\ \hline \
\begin{tabular}{c} LVID Outlet \\ upstream \\ \end{tabular} & 7.4 \(\pm\) 0.3 & 115.2 \(\pm\) 23.8 & 757 \(\pm\) 474 & 84.3 \(\pm\) 8.9 & 1224 \(\pm\) 769 & 1.9 \(\pm\) 0.3 \\ \hline
\begin{tabular}{c} LVID--Inlets \\ upstream \\ \end{tabular} & 7.8 \(\pm\) 0.5 & 69.4 \(\pm\) 15.7 & 444 \(\pm\) 47 & 95.1 \(\pm\) 15.0 & 666 \(\pm\) 117 & 1.4 \(\pm\) 0.2 \\ \hline \hline \end{tabular}  
* Maximum recommended values, according to the Portuguese Irrigation Water Quality Legislation [12]. Legend: Cl–Chloride; TDS—Total Dissolved Solids; SDO—Saturation of Dissolved Oxygen; EC—Electrical Conductivity; SAR—Sodium Adsorption Ratio.  
\end{table} 
Table 1: Physicochemical parameters of water samples, per sampling site (average \(\pm\) standard deviation). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Microorganism Group**} & \multicolumn{3}{c}{**Outlet/Inlet Ratio**} \\ \cline{2-4}  & **LVID*** & **Block II*** & **Rice Fields** \\ \hline Total Coliforms (MPN/100 mL) & 1.01 & 0.82 & 0.08 \\ \hline Fecal Coliforms (MPN/100 mL) & 0.58 & 0.28 & 0.04 \\ \hline Fecal Enterococci (MPN/100 mL) & 1.09 & 0.15 & 0.04 \\ \hline _Enterobacteriaceae_ Amp\({}^{\rm r}\) (CFU/mL) & 0.06 & 102,094 & 3 \\ \hline \hline \end{tabular}  
* LVID, Lis Valley Irrigation District; 2 Block II, Hydraulic Block II.  
\end{table} 
Table 2: Ratio of the mean values of Total Coliforms, Fecal Coliforms, Fecal Enterococci and _Enterobacteriaceae_ Amp\({}^{\rm r}\) counts at the outlet and inlet of the: LVID; Block II; rice fields of Block II. TC values are very widespread, reaching averages above 700 MPN/100 mL in all sampled locations, aside from paddy drainage, with no significant differences between irrigation and drainage water counts. Between the inlet and outlet of Block II there was an 18% decrease in TC counts, and a 92% decrease in rice fields.