Multivariate Discriminant Analysis of Oxygen Saturation Level, Organic Pollution, Thermal Profile, and Chloride Variances between Tlawng and Tuirial River Systems in Aizawl, India

Objectives: The present study was intended to compare the water quality of two rivers, Tlawng and Tuirial as per their dissolved oxygen, biological oxygen demand, chloride and water temperature and to find out the variables which best discriminated the two river systems and seasons among the evaluated parameters by discriminant analysis. Method: Water samples were collected on a monthly basis from the selected monitoring sites from January 2023 to December 2023. Discriminant analysis was done with two different analytical dimensions: temporal (seasonal) and spatial (river system) discriminant analysis, which were performed under four active water quality parameters: dissolved oxygen, biological oxygen demand, chloride and water temperature. Findings: A temporal discriminant analysis produced two canonical discriminant functions (F1 and F2) that explained the total variance in the temporal data set (Wilks' Lambda = 0.451, F = 13.957, p < 0.001). Function 1 was dominated by dissolved oxygen (1.329), while Function 2 showed an inverse relationship with temperature (-0.947) and biological oxygen demand (0.931). For spatial discriminant analysis, a single discriminant function (F1) accounted for 100% of the spatial variance (Wilks' Lambda = 0.668, F = 14.318, p < 0.001), where dissolved oxygen(1.234) was found to be a strong contributor to the discriminant function (1.234) while the remaining parameters showed a low contribution to the discriminant function. Novelty: Comparative data on hydrochemical properties of Tlawng and Tuirial rivers remains scarce; this study provides the first multivariate discriminant analysis of oxygen saturation level, organic pollution, thermal profile, and chloride variances between Tlawng and Tuirial river systems in Aizawl to identify the variables that discriminate between these systems and minimize spatial-temporal noise within the complex monitoring matrix of Aizawl district. Keywords: Discriminant analysis, Dissolved oxygen, Tlawng, Tuirial, Aizawl