Assessment of Water in Terengganu River, Malaysia Using Multivariate Statistical Techniques and Fuzzy DEMATEL

Water is essential in our daily life for life purposes and other activities. Significant water quality degradation due to natural factors and human activities can harm human health and ecosystems. Therefore, water quality monitoring is always necessary for public health and a good ecosystem. This study focuses on assessing river water quality in Terengganu involving several parameters and the location of water monitoring stations along the Terengganu River, which is linked to the second-largest dam in Malaysia. This study uses multivariate analysis such as Principal Component Analysis (PCA) and Agglomerative Hierarchical Clustering (AHC) to assess water quality in the Terengganu River. PCA investigates the origin of each parameter that contributes to river pollution. Before AHC, WQI categorized monitoring stations based on different river pollution zones. The AHC method groups all water monitoring stations based on the level of river pollution zones. Then, this study was continued with the Fuzzy Decision-Making Experiment and Evaluation Laboratory (FDEMATEL) to determine the relationship between river pollution factors. The PCA results yielded five significant factors that accounted for 55.33% of the total variance. AHC classifies three clustered areas: low, medium, and high pollution. Criterion (agricultural and irrigation run-off) is the main causal relationship from FDEMATEL. The results of this study help reveal important information about river water quality in Terengganu to control pollution sources, thus helping to maintain the health of the local population and ecosystem.