Seasonal and Temporal Assessment of Surface Water Quality in Saguling Reservoir Indonesia Using Water Quality Index
Abstract Developments in agriculture, industry, and urban activities have caused deterioration of water resources such as rivers and reservoirs in terms of quality and also quantity. This includes the Saguling Reservoir, which is located in Citarum basin, Indonesia. A review of previous studies reveals that Water Quality Index (WQI) is efficient for the identification of pollution sources as well as for the understanding of temporal and spatial variations in reservoir water quality. The NSFWQI (The National Sanitation Foundation Water Quality Index) is one of the calculation methods of WQI. NSFWQI is commonly used as an indicator of surface water quality is based on Nitrate, Phosphate, Turbidity, Temperature, Fecal coliform, pH, DO, TSS, and BOD parameters. The average index of NSFWQI was determined to be 48.42 during the dry season, 43.97 during the normal season, and 45.82 during the wet season. A calculation of the WQI classified the water quality in the Saguling Reservoir as “bad” in condition. This study reveals that the strongest and most significant correlation between the concentration parameters and the WQI score is the turbidity concentration fecal coli, which is used to determine the required parameters for the calculation of WQI with reduced parameters if needed. This research also conducted nitrate concentration distribution analysis around Saguling Reservoir using the Inverse Distance Weighted method.