Water Quality Influences Self-Purification in the Cihawuk and Majalaya Segments Upstream of the Citarum River, West Java, Indonesia

Self-purification plays an important role in water regulating ecosystem services aimed at protecting river quality from pollutant inputs. The Citarum River is the longest West Java, Indonesia where has declined due to inputs domestic and non-domestic activities. This study aims investigate status of self-purification influence upstream River, Cihawuk Majalaya segments, which are rural urban areas. was determined by deoxygenation rate using Thomas’s slope method, reaeration according O’Connor Dobbins’ method. polynomial component regression (PCR) performed determine significance physicochemical factors on self-purification. rates (k1) areas were 0.044 per day 0.058 day, respectively, while (k2) 0.196 0.156 respectively. These indicate that been disturbed. result also indicates chemical have a significant process, process most significantly influenced physical factors. deterioration poses risk long-term availability resources. Therefore, this research encourages reduction input organic pollutants develops strategic plan for management.