Groundwater Quality Mapping using Geographic Information System: A Case Study of District Thatta, Sindh

Abstract

Access to safe and affordable drinking water for all is an important goal of SDGs (Sustainable Development Goals). Degradation of water quality of coastal aquifers is a major concern throughout the world including the Indus River delta. Looking at the present changing climate scenario, the study was conducted to assess and map the spatial variation in the groundwater quality of district Thatta using GIS (Geographic Information System). The groundwater samples from hundred (100) randomly selected hand pumps of the district were collected such that all union councils of the district were sampled. The water samples were analyzed for different physicochemical parameters, i.e. taste, color, odor, pH, turbidity, EC (Electrical Conductivity), calcium, magnesium, total hardness, chloride, total dissolved solids, and arsenic using standard laboratory techniques. The results of water analysis revealed that 85% of the groundwater samples had TDS (Total Dissolved Solids) concentration beyond the permissible limit described by WHO (World Health Organization). Whereas, all the groundwater samples had chloride concentration beyond permissible limit of 250 mg/l. Analysis for arsenic revealed that only 20% of groundwater samples had a concentration higher than the safe limit of 10 ppb. The study indicated that in most of the areas, the groundwater quality was not as per drinking standards prescribed by WHO, hence was not suitable for drinking purpose. The GIS maps of groundwater quality parameters were prepared using spatial interpolation Kriging tool. These maps provide the visual analysis and interpretation of spatial variability of different groundwater quality parameters, hence are supportive in monitoring and managing the vulnerability of groundwater contamination.

Evaluation of drinking water quality using the water quality index (WQI), the synthetic pollution index (SPI) and geospatial tools in Thatta district, Pakistan

“…2b shows the spatial distribution of turbidity in groundwater in the study area. Higher turbidity levels in groundwater of some areas of the district are likely due to the use of poor quality strainer filter material in the suction line [22]. The high turbidity in the groundwater in the study area is similar to levels of turbidity found in the Southern districts of Sindh province of Pakistan by Memon et al [29].…”

“…1a, b, c, respectively. In the area, the average annual rainfall is about 220 mm, while temperature ranges between 23.8-28.7°C [22,30]. In the area, the groundwater is the primary source of potable water, which is contaminated gradually due to seawater intrusion.…”

“…Geographic information system (GIS) is also a powerful computer-aided tool used for spatial analysis of water quality data [11]. It is also used around the world by many researchers such as El-Hoz et al [11]; Shabbir and Ahmad [15]; Sener et al [18]; Arulbalaji and Gurugnanam [19]; Solangi et al [22]; Abbasnia et al [23] to delineate the spatial variations in the quality of ground and surface water.…”

Drinking Water Quality Mapping Using Water Quality Index and Geospatial Analysis in Primary Schools of Pakistan

“…The excessive TDS effect on drinking water taste may lead to unwanted gastrointestinal irritation and physiological reaction. Previous studies in this area have also confirmed high EC and TDS [44][45][46], which raises serious concerns regarding the health of children in primary schools of Sindh province.…”

Spatiotemporal Dynamics of Land Surface Temperature and Its Impact on the Vegetation

“…Most of its area stretches in two district administrative boundaries of Sindh Province, Pakistan, i.e., Thatta, and Sujawal ( Figure 1). The area hardly receives about 220 mm of rainfall annually [14][15][16][17][18], mostly falls during monsoon periods. According to the 2017 Census, about 1.76 million people are living in these two districts.…”