Groundwater quality risk assessment using hydro-chemical and geospatial analysis

Groundwater quality risk assessment is vital to protect this precious resource, because increasing anthropogenic and agricultural activities combined with limited precipitation deteriorate the groundwater quality particularly in the arid regions. Therefore, the assessment of groundwater quality using hydro-chemical and spatial analysis can provide the guidelines for efficient management of groundwater resources. In present study, a total of 87 samples were collected from various pumping wells in district Multan, Pakistan. These samples were analysed for groundwater quality parameters like electrical conductivity (EC), total dissolve solids (TDS), pH, Na+, Ca2+ + Mg2+, Cl-, CO3,2- HCO3-, sodium adsorption ratio (SAR), sodium percentage (Na%), total hardness (TH), residual sodium carbonate (RSC) and Kelly's ratio (KR). The Wilcox, United States Salinity Laboratory (USSL) and permeability index (PI) diagrams were drawn to classify the water into excellent, good, marginal and poor-quality groundwater for irrigation obligatory. Using the ArcGIS vs 10, an ordinary kriging method with best fit semivariogram model was applied for preparation of spatial distribution maps. According to Wilcox classification, 40% of groundwater samples fall in 'Excellent to a Good' category. USSL diagram showed that 27% of groundwater samples fall in 'Medium Salinity' and 'Low sodium hazard' (C2S1) class. The PI values were found in the range of 22 to 95 meq/L with an average value of 58.5 meq/L. Similarly, the spatial analysis showed that upper part (northeast and northwest) of the Multan District have good quality of groundwater for irrigation. Furthermore, the finding may help to make the spatial management decision for groundwater in the region.

Automated summary

Groundwater quality risk assessment is crucial for protecting the precious resource. This study collected samples and analyzed the quality parameters to classify and map the groundwater quality, providing guidelines and decision-making information for efficient management of groundwater resources.