Water Quality Assessment for Batu Pahat River Basin, Malaysia

In Malaysia, the sharp rise in the population and the expansion of urban developments across the country caused considerable pollution to the water bodies, especially to the rivers. This study aims to assess the non-compliant water quality parameters regarding the Batu Pahat river basin streams in Malaysia. Two different approaches are used: water quality index (WQI) and the new water quality index (NWQI) to categorize the classes, and both results are compared. Moreover, the comparative analysis is done using past data for validation. A distinct difference between WQI and NWQI is recognized. The NWQI method is more likely to categorize a relatively higher class for the selected water quality parameters than the WQI method. The results have shown that out of 25 stations using the WQI method, the water quality parameters of AN, DO, and pH are considered non-compliant parameters. However, using the NWQI method, only DO remains a non-compliant parameter for more than half of the sampling stations. Thus, this research shows a reduction in non-compliant parameters when the WQI method is replaced with the NWQI.