Water quality modelling of the Orhaneli river using the stream water quality computer model QUAL2E

Abstract

A computer modelling study of the Orhaneli River, located in the south of Bursa, wasperformed by making use of the USEP A Enhanced Stream Quality Model `QU AL2E`. Thedata collected by the DSI in the years 1992 and 1993 were used for the model calibrationand validation. Flow rate, DO, BOD, river hydraulogy, ammonia, nitrite ,and nitrate nitrogendata were included in the model. It was difficult to form a general representative model for ariver with such unregulated flow and water quality characteristics, despite this fact, in mostof the studied months, the computed values for the above stated parameters correspondedclosely to the observed instream data, and in the other ones they were fairly clost: to them.At the last step of the study, the model is used as a future water quality management tool. Itis applied to several months' data to forecast the effect of three possible future projects onthe water quality criteria.The model did predict that:• IfTav~anh and Tum;:bilek towns' municipal effluent, and Tun9bilek coal mining andprocessing plant's efIluent are treated, the water quality in the river, especially between194 and 120 km, will improve from second and third quality class to first and secondquality class according to state regulations.• There vvill not be important changes in the water quality clltella of the river when<;marctk dam is constructed, unless there is an extraordinary effect on water quality.Besides slightly decreasing values of DO, there will be significant decreases of BODconcentrations in the reservoir. Thus the dam will be able to serve Bursa as a watersupply.