Determination of pollution load and river water quality status using the pollution index method (case study: Way Sekampung Watershed, Lampung Province, Indonesia)

Abstract Way Sekampung watershed is a significant watershed from the Seputih Sekampung River in Lampung Province. Along the Way Sekampung watershed, there are several WTP intakes. However, the watershed is surrounded by rice field irrigation flows, domestic waste disposal, and tributary estuaries that can potentially reduce water quality values. This study aimed to identify water quality and calculate the water pollution load and the value of water quality status in the Way Sekampung watershed. The parameters tested include temperature, pH, TSS, BOD, DO, ammonia, and total coliform. In this study, the method used to identify water quality is the Pollution Index (IP) method, and for pollution loads, the APL and MPL methods are used. The research area is divided into four segments consisting of 4 water quality sampling points and 1 point source pollution load point. The results obtained parameters that do not meet the quality standards at all points are BOD, COD, and Total Coliform parameters. In calculating pollution load, three parameters are excessive: the Total Coliform parameter 36,295,776 kg/day, COD 738,555.84 kg/day, and BOD 216,691.2 kg/day. The water quality status of the Way Sekampung watershed, with an average total index value of 5.069, is categorized as moderately polluted.