Analysis of river water quality in the upstream of the Code River, Indonesia

The Code River is one of the main rivers of the Opak watershed that crosses the center of Yogyakarta City, Indonesia. Commercial buildings and densely populated areas dominate the basin of the Code River. This condition affects the decline of water quality because people throw their waste into the river. Therefore, it is necessary to know the status of water quality and the class of the river. This research was conducted to find out the water quality and its designation on the upstream of the Code River. The methods used in determining water quality are the pollutant index of the Ministry of Environment Decree No.15 of 2003 and National Sanitation Foundation-Water Quality Index (NSF-WQI). The parameters used in this study are turbidity, DO, BOD, pH, TDS, Total Phosphate, Nitrate, and Fecal Coliform. The result of water quality in the upstream of the Code River, according to the pollutant index method, revealed that the value obtained was 5 - 16, with the status of water quality, was medium polluted and heavily polluted. Whereas according to NSF WQI, the value was at the range of 48 - 56 with the status of water quality was medium to bad.