Water Quality Status of Groundwater in Kathmandu Valley and Analysis of Their Present Situation with Water Quality Index

Abstract

Groundwater is one of the essential natural resources on which the majority of the world's population depends for their daily lives. In Kathmandu Valley, the demand for the water has primarily contributed from groundwater sources and is used for domestic purposes, irrigation, and even for drinking in some areas. However, due to the poor waste management and absence of regular monitoring and control, the water quality index of the groundwater is disintegrating continuously. The main objective of this research was to identify the groundwater quality status of Kathmandu Valley and to identify places with the best quality for drinking within the study area.  42 water samples (no. of samples is seven from each source) were collected during the winter season in December 2021, and major physio-chemical parameters were analyzed. The results revealed that chloride, total hardness, Biological Oxygen Demand (BOD), pH, Electrical conductivity (EC), Total Dissolved Solids (TDS), and turbidity were within the recommendations of the WHO and  National Drinking Water Quality Standards, 2062. However, the Dissolved Ammonia and alkalinity concentrations were higher than the WHO guidelines due to the deposition of the harmful and radioactive waste near the sources and its absorption in the sources. Therefore, The groundwater in the study area is not safe for drinking in all aspects, so treatment is required before the use.