摘要：Jatibarang landfill is the final waste disposal site in Semarang that is located near the Kreo River. The existence of landfill near watershed are related to environmental problems caused by landfill leachate that is not managed properly and cause a decrease in water quality. The purpose of this study was to determine the water quality and pollution index of Kreo and Garang River as the biggest river in Semarang. This research was a descriptive study with an observational approach, consisted of 8 sampling sites and using the pollution index method. The results of this study show that the highest BOD concentration is 36.95 and the lowest is 7 mg/l, the highest COD concentration is 1575 and the lowest is 19 mg/l and the highest DO concentration is 7.75 and the lowest 0.14 mg/l. Based on the pollution index analysis, it shows that the highest Pollution index is 7.38, which means that Kreo and Garang River flow is categorized as polluted and the lowest pollution index is 2.32 classified as moderate polluted. In conclusion, the water quality is decreased due to various activities nearby that marked with moderately polluted and polluted resulted by water quality and pollution index assessment.
