Assessment of the Quality of the Saddang River as A Water Resource in North Toraja Regency Using Storet and Pollution Index

Background: The Saddang River in North Toraja Regency serves as a key water resource for domestic, agricultural, and fishery needs. Increased activity along the watershed may degrade water quality and threaten the sustainability of the river's functions. Objective: This study aims to evaluate the water quality of the Saddang River as a water resource in North Toraja Regency using the STORET and Pollution Index methods. Methods: Sampling was conducted at four observation points (upstream, two middle stations, and downstream) over two weeks, measuring temperature, pH, DO, BOD, COD, TDS, and Total Coliform, with reference to class II water quality standards in Government Regulation Number 22 of 2021. Results: STORET classified the Saddang River as moderately polluted at all stations (scores: −11 to −15). The Pollution Index indicated more severe conditions: in Week 1, ST1 and ST4 were moderately polluted (IP 7.30–8.71) and ST2–ST3 were heavily polluted (IP 10.79–13.18); in Week 2, all stations were heavily polluted (IP 10.21–18.94). Dominant pollutants were Total Coliform, BOD, COD, and low DO (