Spatial and Temporal Analysis of Drinking Water Quality Using GIS-Based Geostatistical Techniques

Regular spatial and temporal assessment of freshwater resources used for drinking water is essential for ensuring water quality and protecting public health. This study evaluated changes in key water quality parameters using a GIS-based Inverse Distance Weighting (IDW) interpolation method. Water samples were collected from four drinking water sources during the wet and dry seasons of 2017 and 2020 and analyzed for ten parameters using the Palin-test method. Spatial distribution maps revealed notable variations in parameter concentrations across the study area for both seasons and years. Overall, the mean concentrations of most parameters increased from 2017 to 2020, except for pH, indicating a general deterioration in water quality. In 2017, all parameters met drinking water standards except pH at half of the sampling locations during the dry season and electrical conductivity (EC) at all locations in both seasons. By 2020, turbidity exceeded allowable limits at most sampling points during both seasons. Additionally, phosphate (PO₄) levels at site S4, and EC and pH at nearly all sites and seasons (except pH at S1 in the wet season), were outside acceptable thresholds. These results demonstrate worsening pollution levels by 2020, likely driven by increasing human activities and natural influences. To safeguard these drinking water sources, it is imperative for stakeholders to establish and enforce regulations that restrict new human activities near water bodies. Furthermore, systematic water quality monitoring, appropriate treatment, and effective protection and management strategies are necessary to ensure sustained access to safe potable water.