Groundwater Quality Assessment Using AveragedWater Quality Index: A Case Study of Lahore City,Punjab, Pakistan

Abstract

Water quality is considered as a major issue in mega cities of developing countries. The city of Lahore has over 10 million populations with the highest population density in the Punjab Province, Pakistan. Groundwater is the main source of drinking water in Lahore. The groundwater quality should be regularly monitored to cope up with drinking water quality issues. The water quality index (WQI), previously used in many studies was usually based on one-year data to analyze the water quality situation of the study area. However, the results obtained from the data, based on single observation from different points may have distortion. This might have occurred due to the inclusion of multiple types of errors induced in the data as a result of improper sampling design, lack of expertise in terms of both sampling method and sample testing, instrumental and human errors, etc. Therefore, the study evaluated the groundwater physicochemical parameters (turbidity, pH, total dissolved solids, hardness, chlorides, alkalinity and calcium) for three years.The averaged water quality index (AWQI) was computed using ArcGIS 10.3 model builder. The AWQI map indicated that the water quality in the study area was generally good except in few places like Anarkali, Baghbanpura, Allama Iqbal Town, Mughalpura and Mozang due to relatively higher turbidity levels. The results of this study can be used for decision making regarding provision of clean drinking water to the city of Lahore. Moreover, the methodology adopted in this study can be implemented in other mega cities as well to monitor groundwater quality.