Geospatial Application of Groundwater Quality Index for Lahore Metropolitan, Pakistan: A Retrospective Approach

The quality of groundwater is significant to be appraised in Pakistan as it is the predominant drinking water source in most of the areas. Unfortunately, increased population and unplanned urbanization have made water quality a severe health risk, especially for Lahore metropolitan. Therefore, continuous monitoring of groundwater quality is required to make informed decisions. Hence, this paper aims to determine water quality index for Lahore using data from 512 wells and application of spatial interpolation techniques. These water quality index maps were then compared with the World Health Organization (WHO) and Pakistan Environmental Protection Agency (EPA) guidelines to determine at-risk areas. The results indicate that the risk of being affected by hazardous concentrations of physical and chemical parameters (pH, turbidity, TDS, Ca, Mg, Fe, Alkalinity, NO2, CO3, HCO3, E. coli) has increased over the past years. It also shows that several groundwater samples are not suitable for drinking purposes, particularly southwestern Lahore has more contamination due to the higher urbanization rate. Despite the data from 512 wells, there are numerous groundwater wells to be tested in order to determine the magnitude of the problem. Studies like this are important for policy making related to sustainable water management and urban planning.