Seasonal Dynamics and Interconnected Physico-Chemical and Biological Water Quality Parameters in the Muari River, West Papua Province, Indonesia

Understanding seasonal dynamics in tropical rivers is crucial to link land use, geomorphology, and ecosystem health. This study examined the seasonal dynamics and interconnections among physico-chemical, sediment, and biological parameters in the Muari River, West Papua, Indonesia. Water quality indicators-including total dissolved solids (TDS), total suspended solids (TSS), conductivity, 5-day biochemical oxygen demand (BODs), chemical oxygen demand (COD), dissolved oxygen (DO), phosphate, nitrate, and total coliform-were measured at three sites (upstream, midstream, and downstream) during the dry (July) and rainy (August) seasons in 2022. Analyses followed Indonesian National Standards (SNI) using calibrated instruments and KAN-accredited laboratory testing. Descriptive statistics and Pearson correlation analyses were employed to assess spatial and temporal variability. Results showed moderate seasonal differences, with elevated TDS, TSS, and total coliform during the rainy season, while DO, BODs, and COD remained stable. Strong positive correlations between TDS and conductivity (r = 0.87) and between TDS and TSS (r = 0.88) indicated runoff-driven transport. Conversely, COD correlated negatively with TDS (r = -0.72) and TSS (r = -0.76), suggesting dilution during high discharge. These findings underscore the necessity of integrated management strategies to sustain tropical river health.