ASSESSMENT AND INDEXING OF GROUNDWATER QUALITY OF DELHI, INDIA USING GIS

Abstract

Ground water is a fundamental and crucial segment of our life supportive network. The ground water assets are being used for drinking, water system and mechanical purposes. There is developing worry on decaying of ground water quality due to “geogenic” and anthropogenic activities. The present study evaluates the groundwater quality of National Capital Territory (NCT) Delhi with respect to drinking and irrigation purpose using Geographic Information System (GIS). The Water Quality Index (WQI) of the groundwater for drinking purposed is also calculated in this work. The data used in this work was collected from CGWB WRIS for the years 2010 and 2015 for twenty-eight locations in the study area. The drinking water quality has been defined using the parameters such as pH, total alkalinity, total hardness, calcium content, nitrate content etc. while irrigation water quality has been defined using the parameters as sodium absorption ratio, salinity hazard , permeability index etc. Spatial distribution maps of these parameter have been generated using QGIS (version 3.10.2). It was observed that in majority of study area the overall concentration of pH, magnesium, potassium, sodium, chloride, fluoride and sulphate in groundwater had been increased over the span of five years from 2010 to 2015.While overall concentration of total hardness, total alkalinity, nitrate and calcium in groundwater had been decreased over the span of five years from 2010 to 2015. Irrigation water quality of majority of the areas was lying under “excellent” to “good” quality category. About 67.8% of the area in 2010 and 78.6% of the area in 2015 under the study comes under “poor” to “unsuitable for drinking category” as revealed by the WQI studies. It can be concluded that overall quality of groundwater of Delhi had been deteriorated from 2010 to 2015. The reasons for this might include increase in population, v over-exploitation of groundwater resources, urbanization and industrialization on large scale.