Browsing by Author "Tezel, Anil Caliskan"

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Citation - Scopus: 1
Exploring Hydrological Response To Land Use/Land Cover Change Using the SWAT Plus Model in the İznik Lake Watershed, Türkiye
(MDPI, 2025) Tezel, Anil Caliskan; Akpinar, Adem; Bor,Asli; Alfredsen, Knut Tore
Land use/land cover (LULC) changes significantly affect hydrological processes in watersheds. In this study, the Soil and Water Assessment Tool (SWAT+) model was employed to investigate the hydrological response to LULC changes in the & Idot;znik Lake Watershed, a region of significant environmental and social importance in the Marmara Region of T & uuml;rkiye. This study provides a novel understanding of water balance dynamics of the & Idot;znik Lake Watershed through hydrological modeling. The SWAT+ model was calibrated and validated against observed monthly flow data from two gauging stations using three objective functions: Nash-Sutcliffe efficiency (NSE), Kling-Gupta efficiency (KGE), and the percent bias (PBIAS). The model was utilized to evaluate the impacts of LULC change on water balance components such as surface runoff, percolation, lateral flow, water yield, and evapotranspiration. The results revealed that the expansion of urban areas and reduction in forest land have led to an increase in surface runoff and a decrease in lateral flow and percolation, which in turn have impacted the overall water yield of the watershed. The findings of this study can inform land use planning and management decisions to mitigate the negative impacts of LULC changes on water resources in the & Idot;znik Lake Watershed and similar regions.
Uncertainty Assessment of the Impacts of Climate Change on Streamflow in the İznik Lake Watershed, Türkiye
(MDPI, 2026) Tezel, Anil Caliskan; Akpinar, Adem; Bor, Asli; Elci, Sebnem
Study region: This study focused on the Iznik Lake Watershed in northwestern T & uuml;rkiye. Study focus: Climate change is increasingly affecting water resources worldwide, raising concerns about future hydrological sustainability. This study investigates the impacts of climate change on river streamflow in the Iznik Lake Watershed, a critical freshwater resource in northwestern T & uuml;rkiye. To capture possible future conditions, downscaled climate projections were integrated with the SWAT+ hydrological model. Recognizing the inherent uncertainties in climate models and model parameterization, the analysis examined the relative influence of climate realizations, emission scenarios, and hydrological parameters on streamflow outputs. By quantifying both the magnitude of climate-induced changes and the contribution of different sources of uncertainty, the study provides insights that can guide decision-makers in future management planning and be useful for forthcoming modeling efforts. New hydrological insights for the region: Projections indicate wetter winters and springs but drier summers, with an overall warming trend in the study area. Based on simulations driven by four representative grid points, the results at the Karadere station, which represents the main inflow of the watershed, indicate modest changes in mean annual streamflow, ranging from -7% to +56% in the near future and from +19% to +54% in the far future. Maximum flows (Qmax) exhibit notable increases, ranging from +0.9% to +47% in the near future and from +21% to +63% in the far future, indicating a tendency toward higher peak discharges under future climate conditions. Low-flow conditions, especially in summer, exhibit the greatest relative variability due to near-zero baseline discharges. Relative change analysis revealed considerable differences in Karadere and Findicak sub-catchments, reflecting heterogeneous hydrological responses even within the same basin. Uncertainty analysis, conducted using both an ANOVA-based approach and Bayesian Model Averaging (BMA), highlighted the dominant influence of climate projections and potential evapotranspiration calculation methods, while land use change contributed negligibly to overall uncertainty.