Analysis of the Water Quality Index (WQI) of the Kupang River to Achieve Sustainable Development Goals (SDGs)

Abstract Human impacts include farming activities, settlements, and industrial waste, all of which degrade the quality of the water in the Kupang River in Central Java. Based on Sustainable Development Goal (SDGs) 6, Clean Water and Sanitation, the Indonesian government targeted a value of 55.5 for the WQI. Descriptive quantitative research was conducted by studying water quality data in the rainy and dry seasons from 2021 to 2023. The results showed that, in general, the Kupang River was in good condition in its upstream parts, and its downstream areas had degraded further into light and heavy pollution. WQI scores were 48 in 2021, 50 in 2022, and 44 in 2023, indicating that the SDG target has yet to be achieved. The significant polluters are high levels of fecal coliform from domestic waste, coupled with low DO and high levels of BOD, COD, and total phosphate. Textile and batik industry wastes increase the level of pollution further downstream. Improvement in wastewater management and public education on environmental conservation is urgently needed for the restoration of the water quality in the river and to support the achievement of SDGs.