The present study aims to carry out a comprehensive water quality assessment of three major water bodies in the Himalayan region – River Ganga, Yamuna and Lake Nainital. For this purpose primary monitoring has been carried out for different seasons. The concentration of physiochemical parameters and heavy metals were found to be more than the desirable levels as prescribed by the BIS/ICMR/WHO. The concentration of physicochemical parameters and heavy metals were high due to the direct disposal of untreated or partially treated domestic and industrial effluent into the water body. In order to interpret and assess the primary monitoring data, various univariate and multivariate statistical techniques were used, which included various tests, principal component analysis (PCA) and cluster analysis (CA). The water quality data was further subjected to Wilcoxon signed rank test and paired t-test and it was found that in both the rivers, the pollution was more during summer and post-monsoon.
The PCA helped in identifying the sources responsible for causing water quality deterioration. The analysis revealed mixed source of pollution (natural, domestic and industrial source of pollution), organic source of pollution such as agro based food processing industry and slaughter house, natural source of pollution such as continuous erosion of soil from the river bank (summer)/ surface runoff and disposal of domestic wastewater respectively as the primary sources of pollution for both the rivers. In order to group alike sampling stations of River Ganga and Yamuna in a cluster, cluster analysis was performed. Two cluster i.e. low pollution and high pollution site for both the rivers were formed .This type of categorization help in sampling few stations of a cluster because these stations act as a representative for other stations of their cluster.
In order to assess the health of the two rivers a water quality index (WQI) has been developed. The index was calculated and compared with the existing values. The WQI indicated at every sampling stations of river Ganga and Yamuna except at G1, Y1 and Y5 (only in winter) the water quality is found to be unsuitable for human consumption and fish cultivation.
The study finally uses mathematical modelling to simulate the water quality. This specifically useful at stretches where primary monitoring data is not available. The simulation was done using the QUAL 2K model. The model was found to perform satisfactorily based on various model performance indicators.
Shodhganga Link (Update by April 2021)