Various methods for calculating the water quality index

Abstract

At present, the most commonly used method to evaluate the quality of a water stream is the application of the Water Quality Index, which may be determined by using different methods. The main purpose of this study is to describe four methods for calculating the Water Quality Index with their advantages and disadvantages: NFS-WQI (National Sanitation Foundation-Water Quality Index), OWQI (Oregon Water Quality Index), WAWQI (Weighted Arithmetic Water Quality Index) and CCME-WQI (Canadian Council of Ministers of the Environment-Water Quality Index). Choosing one of the four methods mentioned above should be based on the study purpose and on the nature of the water stream. These indices have already been used to determine the quality of the Danube water in the all the riverine states. Moreover, the present research reveals that two methods are proved to be useful in determining the Danube water quality, namely: WAWQI (Weighted Arithmetic Water Quality Index) and CCME-WQI (Canadian Council of Ministers of the Environment-Water Quality Index).

Priority Pollutants Monitoring and Water Quality Assessment in the Siret River Basin, Romania

“…Around the world, various methods for WQI were developed after Horton's method [1,21], such as: the National Sanitation Foundation Water Quality Index, the Scottish Research Development Department, the River Status Index, the Canadian Council of Ministers of the Environment Water Quality Index, the British Columbia Water Quality Index, the Overall Index of Pollution, the Oregon Water Quality Index, the Bhargava Method Water Quality Index, the Malaysia Water Quality Index, the Water Contamination Index, the Vaal Water Quality Index, etc. [33,34,54]. Subsequently, WQI was widely applied and accepted in European, African, and Asian countries [26,30].…”

“…The methodology consisted of the following steps: (a) data collection and annual averages account for all monitored parameters; (b) WAWQI calculation, using the following formulas (Equations ( 1)-( 5)) [24,30,34,53,54,56,58]:…”

“…It was proved that WQI represents one of the important evaluation tools that are based on an aggregation function, which allows the analysis of large temporally and spatially-varying water quality datasets turned into a single value [14,21,[30][31][32][33]. Thus, this final value can be easily understood, representing a numerical expression that converts complex water quality data and it is accepted by all national and international water organizations [14,34].…”

Groundwater Hydrogeochemical and Quality Appraisal for Agriculture Irrigation in Greenbelt Area, Iraq

“…The weighted arithmetic module was used to calculate the irrigation water quality index (IWQI) for thirteen parameters in this study. This approach gives data on water-quality evaluations and is calculated using the following formula [22]:…”

Análisis de la calidad del agua en ríos de la cuenca Chancay - Lambayeque, Perú

“…La localización de los ríos y quebradas se puede apreciar en la figura 1. Para el análisis de las características fisicoquímicas y microbiológicas de los ríos y quebradas de la cuenca se han tomado en cuenta los ECAs en lo que corresponde a la Categoría 3 sobre riego de vegetales y bebida de animales, aprobado por el Decreto Supremo N° 004-2017-MINAM (MINAM, 2017) La calidad ambiental del agua expresado en términos índices de calidad fue determinada según sus respectivas metodologías, en lo que respecta al índice ICA-PE, se utilizó la metodología para la determinación del índice de calidad de agua ICA-PE, aplicado a los cuerpos de agua continentales superficiales (ANA, 2018) y para el índice NSF-WQI la metodología aprobada por la National Sanitation Foundation de los Estados Unidos (Călmuc et al, 2018).…”