Application of Remodeled Water Quality Indices and Multivariate Statistical Methods for the Appraisal of Water Quality in a Himalayan Lake

Abstract This study demonstrates and analyses spatio-temporal changes and trends of 15 water quality parameters that were arbitrated from the samples collected at 11 sampling locations during the water quality monitoring across the Dal Lake from September 2017 to August 2020. Further a revised WQI (named WQImin) was developed contingent on multiple regression modeling comprising six key parameters (NH4-N, DO, COD, WT, TUB and NO3-N) so as to ease the course of action and lessen the systematic costs of the water quality assessment. The results signify that the general mean WQI value 81.9 and seasonal average WQI values ranges from 79.44 to 84.55. The quality of water showed seasonal variance, with lowest values in summer, succeeded by autumn and winter, and highest in spring. Moreover, the suggested WQImin model contingent on the selected six critical parameters displayed execution in the evaluation of Dal Lake’s water quality with R2 = 0.99, RMSE value (5.48) and PE value of 6.34%. This manifested that the developed WQImin model can be convenient and efficacious implement to control and determine Dal Lake’s water quality. Further results showed that most of the nutrients were above the threshold value during the monitoring period, which is the leading cause of eutrophication at some places in the lake.