Limnology Laboratory, Department of Biological Sciences, Middle East Technical University, Çankaya, 06800, Ankara, Turkey.
Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark; Sino-Danish Centre for Education and Research (SDC), Beijing, China.
Sci Total Environ. 2017 Mar 1;581-582:413-425. doi: 10.1016/j.scitotenv.2016.12.149. Epub 2017 Jan 6.
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.
年际和年内水位波动以及水流状况变化是地中海湖泊的固有特征。此外，考虑到对水资源有限的地中海地区的气候变化预测，预计空气温度会升高，降水量会减少，这将导致湖泊水位大幅下降以及严重的水资源短缺问题。研究地点是贝希耶尔湖，它是地中海盆地最大的淡水湖，与其他地中海湖泊一样，受到气候变化和为灌溉作物农业过度抽取水资源的威胁。因此，需要实施严格的水位管理政策。在这项研究中，采用了综合建模方法来预测贝希耶尔湖的未来水位，以应对潜在的未来气候变化和土地利用变化。通过将流域模型土壤和水评估工具（SWAT）与支持向量回归模型（ε-SVR）相连接来进行水位估计。基于气候变化模型预测的温度升高和降水减少导致潜在蒸散量增加和总径流量减少。另一方面，流域内各种土地利用情景的影响似乎相对较小。根据ε-SVR 模型结果，水文过程的变化导致所有情景的水位都降低了。此外，MPI-ESM-MR 通用环流模型的输出结果预测表明，按照当前的流出模式，到 2040 年代，贝希耶尔湖可能会干涸。研究结果表明，如果不减少当前的水资源抽取强度，浅地中海湖泊在不久的将来可能会面临干涸和丧失生态系统价值的严重风险。此外，研究结果还表明，在水资源有限的地区，流出管理和可持续利用水资源对于维持湖泊生态系统至关重要。
