A review of water quality index models and their use for assessing surface water quality

Abstract The water quality index (WQI) model is a popular tool for evaluating surface quality. It uses aggregation techniques that allow conversion of extensive data into single value or index. Globally, the WQI has been applied to evaluate (surface and groundwater) based on local criteria. Since its development in 1960s, it become due generalised structure ease-of-use. Commonly, models involve four consecutive stages; these are (1) selection parameters, (2) generation sub-indices each parameter (3) calculation weighting values, (4) compute overall Several researchers have utilized range applications rivers, lakes, reservoirs, estuaries. Some problems they usually developed site-specific guidelines particular region, therefore not generic. Moreover, produce uncertainty large amounts This paper presents comparative discussion most commonly used models, including different structures, components, applications. Particular focus placed parameterization determine sub-indices, functions sources uncertainty. Issues affecting accuracy also discussed.