Author(s): Alper Elci, Selma Ayaz
Linked Author(s): Alper Elci
Keywords: Simulation, river water quality, SWAT model, nutrients, calibration
Abstract: Nutrient-sensitive river basins require special attention with respect to monitoring and controlling point source and diffused source discharges. Water quality models that simulate spatial and temporal changes in surface water quality are important tools in the management of river basin. Particularly, the prediction of diffuse source pollution is an important phase in surface water quality modeling studies. The objective of this study is to predict the spatial and temporal distribution of diffuse source pollution loads for a nutrient-sensitive river basin in north-western Turkey using the GIS-based version of the SWAT model. The results of this study are subsequently used as input data in a related study that involves the development of a surface water quality model for the Mudurnu river. The study area is significant since the Mudurnu river is one of 663 water bodies in the country that are classified as nutrient-sensitive. Primary input data for the SWAT model comprise of land cover data, digital elevation, soil texture map and meteorological records. Average monthly flow rates of surface runoff, lateral subsurface flow, seepage from groundwater, evapotranspiration and deep aquifer recharge are calculated for all sub-basins. The model is calibrated with an automated procedure against measured monthly discharge data. Nutrient loads for each sub-basin are estimated considering basin-wide data on chemical fertilizer and manure usage, population data for septic tank effluents and information about land cover. Diffuse source contaminant loads predicted for each sub-basin indicate that the total annual nitrogen load ranges from 4. 6 to 32. 78 kg/ha/yr, averaging 15. 2 kg/ha per year. Total annual phosphorus load varies between 0. 27 � 7. 23 kg/ha/yr with an average annual basin load of 2. 8 kg/ha. It is concluded that the results from this study are comparable to values published for similar nutrient-sensitive basins and can be directly utilized in related surface water quality modeling studies
Year: 2017