title: Future water availability in the largest freshwater Mediterranean lake is at great risk as evidenced from simulations with the SWAT model.
abstract: Inter- and intra-annual water level fluctuations and changes in water flow regime are intrinsic characteristics of Mediterranean lakes. Additionally, considering climate change projections for the water-limited Mediterranean region, increased air temperatures and decreased precipitation are anticipated, leading to dramatic declines in lake water levels as well as severe water scarcity problems. The study site, Lake Beyşehir, the largest freshwater lake in the Mediterranean basin, is - like other Mediterranean lakes - threatened by climatic changes and over-abstraction of water for irrigated crop farming. Therefore, implementation of strict water level management policies is required. In this study, an integrated modeling approach was used to predict the future water levels of Lake Beyşehir in response to potential future changes in climate and land use. Water level estimation was performed by linking the catchment model Soil and Water Assessment Tool (SWAT) with a Support Vector Regression model (ε-SVR). The projected increase in temperature and decrease in precipitation based on the climate change models led to an enhanced potential evapotranspiration and reduced total runoff. On the other hand, the effects of various land use scenarios within the catchment appeared to be comparatively insignificant. According to the ε-SVR model results, changes in hydrological processes caused a water level reduction for all scenarios. Moreover, the MPI-ESM-MR General Circulation Model outputs produced the most dramatic results by predicting that Lake Beyşehir may dry out by the 2040s with the current outflow regime. The results indicate that shallow Mediterranean lakes may face a severe risk of drying out and losing their ecosystem values in the near future if the current intensity of water abstraction is not reduced. In addition, the results also demonstrate that outflow management and sustainable use of water sources are vital to sustain lake ecosystems in water-limited regions.
authors.affiliation: Limnology Laboratory, Department of Biological Sciences, Middle East Technical University, Çankaya, 06800, Ankara, Turkey. Electronic address: tuba.bucak@metu.edu.tr.
authors.forename: Tuba
authors.initials: T
authors.lastname: Bucak
authors.affiliation: Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark; Sino-Danish Centre for Education and Research (SDC), Beijing, China.
authors.forename: Dennis
authors.initials: D
authors.lastname: Trolle
authors.affiliation: Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark.
authors.forename: Hans Estrup
authors.initials: HE
authors.lastname: Andersen
authors.affiliation: Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark.
authors.forename: Hans
authors.initials: H
authors.lastname: Thodsen
authors.affiliation: Limnology Laboratory, Department of Biological Sciences, Middle East Technical University, Çankaya, 06800, Ankara, Turkey; Department of Biology, Faculty of Science and Arts, Bozok University, 66900 Yozgat, Turkey.
authors.forename: Şeyda
authors.initials: Ş
authors.lastname: Erdoğan
authors.affiliation: Limnology Laboratory, Department of Biological Sciences, Middle East Technical University, Çankaya, 06800, Ankara, Turkey.
authors.forename: Eti E
authors.initials: EE
authors.lastname: Levi
authors.affiliation: Limnology Laboratory, Department of Biological Sciences, Middle East Technical University, Çankaya, 06800, Ankara, Turkey.
authors.forename: Nur
authors.initials: N
authors.lastname: Filiz
authors.affiliation: Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark; Sino-Danish Centre for Education and Research (SDC), Beijing, China.
authors.forename: Erik
authors.initials: E
authors.lastname: Jeppesen
authors.affiliation: Limnology Laboratory, Department of Biological Sciences, Middle East Technical University, Çankaya, 06800, Ankara, Turkey; Kemal Kurdaş Ecological Research and Training Station, Lake Eymir, Middle East Technical University, Ankara, Turkey. Electronic address: meryem@metu.edu.tr.
authors.forename: Meryem
authors.initials: M
authors.lastname: Beklioğlu
keywords: Climate change; Drying out; Land use; Outflow; Water level; ε-SVR