SPATIAL ANALYSIS OF GROUNDWATER SOURCE POTABILITY IN BARANGAY LAGAO,GENERAL SANTOS CITY

The study aimed to trace the water source of Barangay Lagao, General Santos City such as pitcher pumps, flowing and shallow tube wells, assess and analyse the groundwater quality based on the Electrical Conductivity (Salinity),Turbidity, pH Level, Total Dissolved Solids (TDS), Total Suspended Solids (TSS), and Hardness, and to generate potability map of the groundwater source of Barangay Lagao, General Santos City. The physico-chemical results were compared to the standard guideline values as recommended by the Philippine National Standard for Drinking Water (PNSDW) and World Health Organization (WHO) for drinking in order to have an overview of the present groundwater quality. Using QGIS methods, potability maps of pH, TDS, EC, TH, TSS, Electrical Conductivity and Turbidity, have been created. An interpolation technique, ordinary Inverse Distance Weighted (IDW), was used to obtain the spatial distribution of groundwater quality parameters. The spatial analysis of groundwater quality of the study area shows that the interpreted water quality with respect to EC indicates that only 35.29% of the study area groundwater lies in bad range for drinking water purposes. The spatial distribution map of Total Hardness shows that a majority of the groundwater samples（63.53%) falls in the very hard category. It is also observed that the majority of the samples displayed the turbidity value within the highly potable, except for five samples (21, 28, 29,32 and 80) which presented the turbidity value exceeding the permissible limit which is said to be currently not potable. WQI was used to assess the potabilty of groundwater from the study area for human consumption. From the WQI assessment, over 18.82% of the water samples fall within the “Good”＇ and “Unfit for Drinking” categories, suggesting that some of the groundwater from the Barangay Lagao deep aquifer is used only for irrigation purpose.