Evaluation of groundwater quality of Prayagraj city using entropy water quality index (EWQI) and new integrated water quality index (IWQI)

Information about groundwater quality and their suitability for drinking purpose is important for the society. Two indices namely entropy water quality index (EWQI) and new integrated water quality index (IWQI) have been used to assess the groundwater quality of Prayagraj city, India. The synthesis of outcomes is presented through geographical information system (GIS). Fifteen groundwater quality parameters namely pH, electrical conductivity, hardness, total dissolved solids, alkalinity, calcium, sodium, magnesium, potassium, nitrate, bicarbonate, chloride, sulphate, fluoride and iron were evaluated during pre- and post-monsoon season. It is revealed that the groundwater in the city is good and hard type with excess concentration of iron. On the basis of EWQI, groundwater is good and suitable for drinking purposes both in pre- and post-monsoon period. IWQI has resulted that during pre-monsoon water quality in 17% of the area is unsuitable for drinking with 25% area having poor water quality but during post-monsoon, the same area has been increased to 25% and 42%, respectively. About 50% of the area is categorised as marginal quality water during pre-monsoon but it is reduce to 33% during post-monsoon. Present study suggests the requirement for regular assessment of groundwater quality for its healthier utilization and management.