Table 2
Empirical equations for obtaining the WQI's 
| Parameter | Equation | |
|---|---|---|
| BOD5,20 |  | (2) |
| Fecal coliforms (E. coli) |  | (3) |
| Total phosphorus |  | (4) |
| Total nitrogen |  | (5) |
| Dissolved oxygen |  | (6) |
| pH |  | (7) |
| Total suspended solids |  | (8) |
| Turbidity |  | (9) |
| Temperature |  | (10) |
| Parameter | Equation | |
|---|---|---|
| BOD5,20 | | (2) |
| Fecal coliforms (E. coli) | | (3) |
| Total phosphorus | | (4) |
| Total nitrogen | | (5) |
| Dissolved oxygen | | (6) |
| pH | | (7) |
| Total suspended solids | | (8) |
| Turbidity | | (9) |
| Temperature | | (10) |
Temperature is a constant, because a low variation in the values was considered over the time series.