2.3. WQI Weighted Method
In this widely used method, the WQI is calculated as the weighted sum of the different sub index scores [31] [32]. The individual parameter scores are aggregated into a final index value (between 0 and 100).
The following empirical equation was used for the determination of the WQI [31]-[33]:where Ci
is the normalized value of the parameters and Pi
is the relative weight of each parameter in term of
its importance for aquatic life and drinking water. The parameter Pi has a maximum value of 4, assigned to pa-
rameters of relevant importance for drinking water, such as Dissolved Oxygen (DO), Suspended Sediments (SS)
and Water Temperature (Tw). Also, the minimum value assigned to parameters with minor relevance is the value of 1. Table 3 shows the weights and the normalization factors of the parameters used in this study. WQI Weighted Method is also an objective based index similar to the CCME WQI (Table 1). As such, the index will provide an indication if the water quality is fair, good, etc.