In this study, a water quality model of Firtina Creek was used as an evaluative tool to estimate the spatial distribution of several water quality related variables together with the nutrient loads that are transported to the Eastern Black Sea. Firtina Creek is an important habitat within the Eastern Black Sea ecosystem due to the fact that it is the primary spawning area for Black Sea Trout (Salmo trutta labrax, Pallas 1811). It can also be considered as all important water resource because of its relatively high flow rate and the water quality, which indicates that the stream is still not seriously polluted. Studies performed in this river indicate that external activities along the Firtina Creeks watershed (such as road construction and pollution from a hydroelectric darn construction) have led to various changes within the ecosystem. In this study, the possible effects of three additional fish farms with a production capacity of 50 tons, located oil the Firtina Creek within 1 kml distance from each other were evaluated in terms of their effects on the streams water quality. QUAL2E was used as the water quality modelling and analysis tool. The water quality data gathered from various data sources and the model were used to estimate dissolved oxygen (DO), biological oxygen demand (BOD(5)) and nutrients along the stream.