Water quality indices: challenges and applications—an overview

Abstract

Water quality index (WQI) is one of the most important and valuable tool used for assessing the overall water quality as it presents the final form in a single value. The concept and development of the WQI was initially developed by Horton in 1965. Since then many other transformations have occurred in the determination of WQI as proposed by different scientists and researchers. The index tends to facilitate the effective management of numerous water sources for both surface and groundwater and specifies their suitability for various uses. In general, continuous monitoring and assessments of different water quality parameters are highly complex in nature leading to generation of large voluminous datasets which are often difficult to interpret and is often uneconomical. In this context, the WQI incorporates the complex nature of different water quality parameters and helps to form a connection among these, culminating in a single value categorizing the water and this information is presented to different governmental, public agencies and regulatory authorities. The review paper presents detailed and operational descriptions along with mathematical calculations providing an insight about the development and the utility of WQIs. It has been observed that though there are many index methods available but no one single method is recognized globally to fulfill the objective of water quality management. The review also presentsWQIs in an easy and streamlined manner which may be further used to have a reliable data for attaining quality of water.