Spatio-temporal analysis of river water pollution levels in the Angke-Pesanggrahan watershed

River water is an important part of people's lives, both in quantity and quality. Various utilizations will influence the decline in water quality, especially from household, industrial, and solid waste or garbage disposal. One of the watersheds affected by this anthropogenic influence is the Angke-Pesanggrahan watershed in Jakarta Province. The study was conducted at 31 observation points of several rivers, such as the Angke, Sekertaris, Sepak, Mookervart, Grogol, Cengkareng, Kamal, and Pesanggrahan Rivers. This study aims to analyze the water pollution level spatio-temporal for eight periods in 2021-2022. The dynamics of the pollution level are analyzed by the Pollution Index (PI) using water physical-chemical-biological parameters. The pollution level in each river was then mapped using ArcGIS software. The pollution level of this watershed was light to heavily polluted (PI value of 4.13-19.34). The status of river water quality in almost all rivers is likely to be worse in 2022 than in 2021. High pollution levels are generally found in almost all rivers, especially the Sekertaris and Sepak Rivers. Pesanggrahan River has a better status, with an average PI of 8.06 (moderately polluted). Parameters often do not meet quality standards: color, TSS, ammonia, free chlorine, H2S, BOD, COD, DO, nitrite, MBAS, fecal coliform, and total coliform. Pollution in the watershed needs to be resolved by involving local stakeholders, implementing communal WWTP, applying for stricter wastewater discharge permits, and continuously educating and empowering the community on sustainable river management.