Multivariate Statistical Approach to Study Spatiotemporal Variations in Water Quality of aHimalayan Urban Fresh Water Lake

Abstract

Physicochemical parameters determining Dal Lake water quality were evaluated at four different sites during 2016–2017 in four different seasons Spring (April), Summer (July), Autumn (October), and Winter (January). The observed physicochemical values were analyzed by statistical (discriminant analysis) and arithmetic (WQI) methods to ascertain sources and levels of pollution. Discriminant analysis helped to access the contribution of each physicochemical parameter in water quality in the context of sampling sites (spatial) and seasons (temporal) to discriminate pollution loading between sites and as well as seasons. Factors such as temperature, alkalinity, ammoniacal nitrogen, total phosphorous, and orthophosphorous exhibited a strong contribution in the discrimination of sampling sites, while factors such as temperature, alkalinity, hardness, BOD, nitrate nitrogen, and total phosphorous exhibited a strong contribution in the discrimination of sampling seasons. The WQI values for four sampling sites were calculated and indicated that the water at Site I was the most contaminated followed by Site IV, while Site III was the least contaminated. Thus, highlighting that the pressure of anthropogenic activities is subjecting Dal Lake to an unnatural death.