Assessment of water quality index in the St. Thomas Mount Block using GIS and remote sensing

Groundwater is an essential natural resource for securing drinking water and plays a significant role in human wellbeing. However, in recent times the pressure on groundwater has increased both quantitatively and qualitatively. The drinking water sources are threatened by contamination through human exploitation. The objective of this study is to assess and map the spatial distribution of groundwater quality in the St. Thomas Mount Block of Kancheepuram District, Tamilnadu, using geographical information systems (GIS) and remote sensing (RS). This block has been experiencing rapid industrialization and urbanization, and this has made people in the area depend on groundwater resources. The suitability of water for drinking purposes in the study area is calculated using water quality index (WQI), considering land use changes. WQI is calculated by using standards of drinking water quality recommended by the Bureau of Indian Standards 10500:1993 (BIS) and the Indian Council for Medical Research (ICMR). In the present study, nine water-quality parameters were considered for computing WQI. The inverse distance-weighted (IDW) spatial interpolation technique was used to estimate the spatial distribution of groundwater parameters and WQI. It was observed from the WQI map that around 76.5% of the total area is unfit for drinking.