Spatial and Temporal Variation of Water Quality Index

In ancient countries like India, every development is pioneered around the water bodies. India homes for a few hundreds of lakes which accounts for both natural and artificial lakes that are considered an important part of the ecological as well as religious cycle. Over the past century, there is a prodigious increase in human settlements, anthropogenic pressure and public effluent sources around the lakefront resulting in the degradation of the lake in both aspects of quality and quantity. Practicing appropriate remediation techniques can improve a lake’s water quality, so there is a definite need for continuous monitoring of a lake (Yadav et al., 2014). The arduous and tedious task of assessing the lake water quality based upon individual parameters (Hou et al., 2016) is evaded by practicing different approaches like statistical approaches, water quality indices, etc (Guo et al., 2018.). Over the past two decades, WQI is on a positive gradient of importance in assessing the surface water quality of the lake and river bodies (Kachroud et al., 2019). The main objective of WQI is to provide a score of water quality by aggregating different physical, chemical and biological parameters. The history of WQI dates back to 1965 as studied by Horton et al. (1965). Since then there has been the development of various new indexes by using some computational methods like fuzzy techniques, neural networks techniques, Prime-component analysis, etc. The sequential framework for the development of a WQI is shown in Fig. 5.1.