EN
The Drina River is the biggest tributary of the Sava River, created by the merger of the Tara and Piva rivers at Šćepan Polje. The Drina represents the border between Serbia and Bosnia and Herzegovina. Water quality index (WQI) is a numeric expression used to evaluate the quality of water bodies and make it more easily understood by managers. In this study, the water quality status and the spatial and temporal trends along the Drina were assessed through the application of seven WQI parameters, to an eight-year public database of environmental data (2004-11). Water quality of the Drina is one of the significant factors taken into consideration in evaluation of sustainability of the development of this region and it is controlled by complex anthropogenic activities and natural factors. Values of pH grew steadily from CP1 to CP3, but on CP4 values of pH were lower (8.11) than on two previous control points (CP2 8.14 and CP3 8.16). O₂ saturation shows highest values at CP1 121.3%, while the lowest values were observed at CP3 101.8%. BOD₅ at all four CPs shows that water quality of the Drina can be classified as I class (< 2 mg/l). According to statistical data processing we can state that Drina water quality at all four control points allows for its exploitation.