Swat modeli kullanılarak gürdük havzası su kalitesini geliştirme alternatiflerinin değerlendirilmesi

Gürdük Watershed is a part of Gediz Watershed and it is located is in Aegean Region. The Watershed covers an area of approximately 3,200 km2. Within the boundaries of Gürdük Watershed, there are 10 districts of Manisa. Since Gürdük Watershed has fertile soil and a suitable climate for agriculture, the region is at the forefront of agricultural production in Turkey. More than 50 % of the watershed consists of areas with agricultural lands. Within of the scope of this thesis, the current pollution status of the Gürdük Watershed due to point and diffused sources was examined via considering Surface Water Quality Regulation and three different Water Quality Indices (WQIs) and evaluation of the alternatives to improve water quality in terms of Sediment, and Nitrate was conducted by using Soil and Water Assessment Tool (SWAT). Meteorological data of the watershed, digital elevation model (DEM), land use/land cover (LULC) map, soil texture properties and point discharges from both municipal and industrial waste water treatment plants and the information on agricultural management are needed to set-up SWAT model. The calibration of the Model was done via SWAT-CUP for stream flow, sediment, and nitrate by using monthly data from DSİ Monitoring Station. Different management alternatives were identified to improve water quality of Gürdük Watershed considering the point and diffused sources, namely decreasing the amount of fertilizer usage, increasing the WWTP efficiencies and applying conservation tillage. Goal of this study was to evaluate the water quality in Gürdük Watershed and develop management strategies to improve the water quality. Results of this study have shown that, decreasing the fertilizer usage and improving the waste water treatment efficiency can significantly increase the water quality of the watershed.