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Abstract

Climate change would augment water scarcity problems in Mediterranean catchments. • Future water level changes was simulated by linking SWAT model to ε-SVR model. • Climate change has a major impact on hydrology while effects of land use are minor. • Outflow management is critical to prevent Mediterranean lakes from diminishing. 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

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... The river water temperature increases slightly less than the air temperature. The least temperature rise occurs in basins fed by large amounts of groundwater (Bucak et al., 2017). Biological and chemical processes develop largely depending on the water temperature. ...
... In Turkey, with the rapid population growth, the decrease in the area per capita, the widespread use of industry, the mechanization of agriculture are the leading factors in the pollution of the environment and water (Bucak et al., 2017). It is known that today, pollution has reached significant levels in many water basins as a result of domestic, industrial wastewater and irregular agricultural activities that cannot be kept under control in Turkey (Yenici, 2010;Kaya et al., 2019;Menteş et al., 2019;Bozkurt, 2013;Yılmaz, 2019;Bucak et al., 2017). ...
... In Turkey, with the rapid population growth, the decrease in the area per capita, the widespread use of industry, the mechanization of agriculture are the leading factors in the pollution of the environment and water (Bucak et al., 2017). It is known that today, pollution has reached significant levels in many water basins as a result of domestic, industrial wastewater and irregular agricultural activities that cannot be kept under control in Turkey (Yenici, 2010;Kaya et al., 2019;Menteş et al., 2019;Bozkurt, 2013;Yılmaz, 2019;Bucak et al., 2017). Increased summer temperatures caused by climate change, reduced winter rainfall (especially in the western provinces), loss of surface waters, frequent drought, soil degradation, erosion in coastal areas, and frequent floods are threatening the existence of water resources and quality in Turkish basins (Republic of Turkey Ministry of Development, 2018). ...
Article
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Climate change, which is caused by the greenhouse gases released into the atmosphere by humans, disrupting the temperature, rainfall, and humidity balance on the earth, makes itself felt more and more every day. The effects of climate change are seen in oceans, habitats, briefly all over the world, from the equator to the poles. With the impacts of these effects, the polar glaciers are melting, the seawater level rises and soil losses increase in the coastal areas, while the severity and number of hurricanes, and floods increase in some parts of the world, while long-term droughts and desertification have started in some other regions. Climate change also affects water resources greatly, and it occurs as a decrease in water resources, forest fires, and related ecological deterioration. As a result of the decrease in the water flow in the river basins, water shortage started in the cities, agricultural production decreased and caused the expansion of arid or semi-arid areas. In this study, the impacts of climate change on Turkish basins were investigated and the measures to be taken were examined. Possible problems to be encountered in the future were mentioned and suggestions were made about what to do in the basins.
... Ellos concluyeron que el caudal se incrementó en un 10% por la conversión de la vegetación nativa a un uso de suelo mixto. Aunque se ha demostrado Bucak et al., 2017;Grey et al., 2014) que la cubierta forestal natural per se no garantiza más caudal o una regulación del flujo hídrico base con respecto a las cuencas hidrográficas deforestadas y la reforestación no aumenta el caudal o regulariza el flujo hídrico base en el corto y mediano plazo. Por lo que se ha concluido que la literatura de cuencas tropicales no es suficiente para evaluar los servicios hidrológicos (Ozment & Filoso, 2017), por ejemplo, los efectos de la edafología en la hidrología local. ...
... El modelo hidrológico Soil and Water Assesment Tool (SWAT) (Arnold et al., 1998) simula y predice el balance de agua bajo el efecto de la deforestación en escalas de cuencas (Zhang et al., 2016;Gassman et al., 2007). SWAT se ha utilizado para evaluar servicios hidrológicos en todo el mundo (Ahn y Merwade, 2016;Brauer et al., 2016;Francesconi et al., 2016;Bucak et al., 2017;Her et al. 2017), por lo que el modelo puede usarse como una herramienta efectiva para examinar las respuestas hidrológicas ante la deforestación (Pereira et al., 2016). Sin embargo, una de las limitaciones de la modelación es la ausencia de datos a escalas apropiadas para obtener buenas predicciones, y además se asume la necesidad de datos de resolución fina para realizar la modelación. ...
... The two GCMs used in the (Bucak et al. 2017) study were able to model the trends of contemporary climate data; however, the precipitation and temperature predictions for the future varied widely. Although the direction and seasonality of the changes exhibited similar patterns, the magnitude of the changes differed between the climate models. ...
Thesis
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La demanda de la población sobre los ecosistemas está creciendo y ejerciendo presión sobre los servicios ambientales hidrológicos de cuencas tropicales, como es la cantidad de agua y la regulación de las aguas de superficie y subterránea. Aunque, puede parecer que los bosques absorben el agua disponible, dejando menos cantidad para el uso humano. Una revisión de literatura sobre la relación bosque- agua en cuencas tropicales deja ver que esta relación es más compleja, y que los servicios hidrológicos de provisión y regulación que se comercializan en los esquemas de Pagos por Servicios Ambientales (PSA) normalmente no se cuantifican de manera adecuada, aunque se aceptan de forma pragmática. En esta tesis se evaluó la cantidad y regulación del agua en cuencas donde se ha concedido el PSA. Primero se analizó si las predicciones del caudal mejoran al utilizar datos de suelos y vegetación disponibles al público vs datos finos. Luego se analizó cómo la deforestación que ocurrió en la cuenca afectó el caudal y el flujo hídrico base, y cuál hubiera sido el impacto si continuara la deforestación. Por último, aunque el modelo SWAT es una herramienta que ayuda en la cuantificación de los servicios hidrológicos, se realizó una revisión sistemática de la literatura para conocer el alcance del modelo en la simulación y predicción de las alteraciones en los regímenes hidrológicos. Esfuerzos adicionales se realizaron para entender la relación bosque-agua, como son la exploración del comportamiento hidrológico a escalas de cuencas en la modelación SWAT y medición de lluvia-escurrimiento en cuencas pareadas.
... The two gcm´s used in the Bucak et al. (2017) study were able to model the trends of contemporary climate data; however, the precipitation and temperature predictions for the future varied widely. Al-though the direction and seasonality of the changes exhibited similar patterns, the magnitude of the changes differed between the climate models. ...
... Thompson et al. (2015) reported 0.8% to 52% reductions in annual runoff in their simulations for the Inner Niger Delta. Similarly, large variations in river discharges emerged in the Bucak et al. (2017) study, from +7% to −20% by the 2040s, from +1% to −18% by the 2070s, and from −14% to −52% by the end of century due to variations in gc-m´s and rcp´s. Bucak et al. (2017) generated combinations of land use/ land cover with different climate change scenarios in Mediterranean watersheds. ...
... Similarly, large variations in river discharges emerged in the Bucak et al. (2017) study, from +7% to −20% by the 2040s, from +1% to −18% by the 2070s, and from −14% to −52% by the end of century due to variations in gc-m´s and rcp´s. Bucak et al. (2017) generated combinations of land use/ land cover with different climate change scenarios in Mediterranean watersheds. They mentioned that although the effects of land use scenarios were not significant, decreased runoff with agricultural expansion scenario might indicate an increased water demand for irrigation. ...
Chapter
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Quantitative knowledge about the alterations in hydrologic regimes is essential in order to prepare for climate change, flooding, drought, and other human-induced changes to the water cycle. The Soil and Water Assessment Tool (swat) allows the watershed-modeling tool to characterize the existing hydrological regimen and to model future changes. However, watershed modeling requires large, diverse and heterogeneous data in addition to important computational and storage resources. The objectives of this study are to provide an overview of efforts using swat to quantify alterations in hydrologic regimes, to ascertain the model’s capacity in the simulation of watershed and their relationship with the coastal zone through a systematic review in swat’s literature. Key words: Coastal zone, climate change scenarios, El Niño/Southern Oscillation (enso) phenomena, flood impacts, hydrologic regimes, swat, watershed.
... Türkiye'de SWAT modeli uygulamaları yaygınlaşmaktadır. Literatür araştırması sonucu Türkiye genelinde SWAT modeli uygulamalarıyla ilgili 17 adet akademik makale tespit edilmiştir [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. ...
... Türkiye'de yapılan çalışmalar kapsamında, Bucak ve arkadaşları [8], Beyşehir gölünde gelecekteki su mevcudiyetinin risk altında olunduğunu SWAT simülasyonları ile kanıtlamıştır [8]. Başka bir çalışmada Ertürk ve arkadaşları [18] SWAT modelini kullanarak Dalyan bölgesi için yeraltı suyunun dış etkilere karşı hassasiyetini değerlendirmiştir [18]. ...
... Türkiye'de yapılan çalışmalar kapsamında, Bucak ve arkadaşları [8], Beyşehir gölünde gelecekteki su mevcudiyetinin risk altında olunduğunu SWAT simülasyonları ile kanıtlamıştır [8]. Başka bir çalışmada Ertürk ve arkadaşları [18] SWAT modelini kullanarak Dalyan bölgesi için yeraltı suyunun dış etkilere karşı hassasiyetini değerlendirmiştir [18]. ...
Article
Antropojenik aktiviteler ve iklim değişikliği Küçük Menderes Havzası’nın su kaynaklarını olumsuz bir şekilde etkilemektedir. Nüfus artışı ve kontrolsüz su kullanımları havzayı su fakiri haline getirmiştir. Havzadaki problemlere çözüm sunabilecek modelleme çalışmaları gereklidir. Bu çalışmada, SWAT(Toprak ve Su Değerlendirme Aracı) yazılımı kullanılarak Küçük Menderes Alt Havzası için hidrolojik model oluşturulmuştur. Modelin kalibrasyonu ve duyarlılık analizi SUFI-2 (Sıralı Belirsizlik Uygunluğu) metodu kullanılarak SWAT-CUP (SWAT Kalibrasyon Belirsizlik Programları) ile yapılmıştır. Model en çok CN2, SOL_BD (katman#), RCHRG_DP ve SOL_K (katman#) parametrelerine duyarlı olmuştur. Modelin performansı P-faktör, R-faktör ve objektif fonksiyonlarla değerlendirilmiştir. P-faktör değeri %61 ile %80 aralığında izlemeleri eşlemiştir. Objektif fonksiyonlara göre model performansının yeterli seviyede olduğu değerlendirilmiştir. Bu çalışma, havzada iklim değişikliğinin ve en iyi yönetim uygulamalarının etkisini anlamak için yapılan çalışmalar için ve su kalitesi modellemesi çalışmaları için bir altlık oluşturmaktadır.
... Its north-eastern part is dominated by intensive crop farming, while the western part features forested mountains with small areas of low-intensive agriculture. Water availability of Lake Beyşehir is threatened by unmanaged water abstractions, already requiring water transfers from a nearby basin into the lake (Bucak et al., 2017). As is commonplace in most Mediterranean areas, the low water availability in the basin makes the system vulnerable to further water cutbacks, which are expected in the future (Levi et al., 2016). ...
... Daily meteorological data for precipitation, temperature, wind, solar radiation and relative humidity for the stations Beyşehir and Seydişehir were available for the period 1960 to 2012. The SWAT model for the hydrological balance was used to simulate evapotranspiration, infiltration, percolation, runoff and nutrient loads for Lake Beyşehir (Bucak et al., 2017). For the setup of the two lake models PCLake and GLM, daily meteorological and physico-chemical data were required. ...
... Climate change was mainly driving the TP changes in Lake Beyşehir and Odense. In Southern Europe, water levels are expected to decrease dramatically due to reduced precipitation (Bucak et al., 2017), causing an up-concentration of TP. In addition, rising water temperatures will induce enhanced nutrient remobilization from sediments and thus increased TP concentrations in surface waters (Bucak et al., 2018). ...
Article
There are infinite possible future scenarios reflecting the impacts of anthropogenic multiple stress on our planet. These impacts include changes in climate and land cover, to which aquatic ecosystems are especially vulnerable. To assess plausible developments of the future state of European surface waters, we considered two climate scenarios and three storylines describing land use, management and anthropogenic development (‘Consensus’, ‘Techno’ and ‘Fragmented’, which in terms of environmental protection represent best-, intermediate- and worst-case, respectively). Three lake and four river basins were selected, representing a spectrum of European conditions through a range of different human impacts and climatic, geographical and biological characteristics. Using process-based and empirical models, freshwater total nitrogen, total phosphorus and chlorophyll-a concentrations were projected for 2030 and 2060. Under current conditions, the water bodies mostly fail good ecological status. In future predictions for the Techno and Fragmented World, concentrations further increased, while concentrations generally declined for the Consensus World. Furthermore, impacts were more severe for rivers than for lakes. Main pressures identified were nutrient inputs from agriculture, land use change, inadequately managed water abstractions and climate change effects. While the basins in the Continental and Atlantic regions were primarily affected by land use changes, in the Mediterranean/Anatolian the main driver was climate change. The Boreal basins showed combined impacts of land use and climate change and clearly reflected the climate-induced future trend of agricultural activities shifting northward. The storylines showed positive effects on ecological status by classical mitigation measures in the Consensus World (e.g. riparian shading), technical improvements in the Techno World (e.g. increasing wastewater treatment efficiency) and agricultural extensification in the Fragmented World. Results emphasize the need for implementing targeted measures to reduce anthropogenic impacts and the importance of having differing levels of ambition for improving the future status of water bodies depending on the societal future to be expected.
... Downward trends in precipitation were consistent with previous studies conducted in Southern Europe (Feyen et al. 2020) and in the Mediterranean Basin (Altın 2020; Erol and Randhir 2012;Ertürk et al. 2014). However, Bucak et al. (2017) indicated that precipitation would increase by 10 mm (HadGEM2-ES) or decrease by 35 mm (MPI-ESM-MR) from the 2010s to 2090s at the Lake Beyşehir watershed, adjacent to Altınapa Reservoir watershed, under the RCP4.5 scenario. GCM models could show regional characteristics and some uncertainties in simulating regional effects are possible (Monerie et al. 2017). ...
... A few previous studies investigated climate change impacts on water resources of semi-arid Turkey. Bucak et al. (2017) projected increase in temperature and decrease in precipitation in Beysehir Basin in Konya by using data from the GCMs downscaled to local conditions. They found that streamflow would decrease in the future, particularly towards the end of the century. ...
... GFDL-ESM2M, HadGEM2-ES, and MPI-ESM-ER predicted that mean annual temperature would be 0.4 °C, 3.3 °C, and 3.3 °C higher during the 2071-2098 period, respectively. The temperature increases expected in the Altınapa Reservoir Watershed and in other Mediterranean basins in Turkey are consistent with expectations presented in the latest IPCC report (2018).At the local level,Bucak et al. (2017) andGorguner et al. (2019) also projected increases in temperatures by using data from GCMs downscaled to local conditions. All GCMs predicted temperature increases in spring, summer, and winter for the periods 2041-2070 and 2071-2098 compared to the 2021-2040 period. ...
Article
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Climate change can have severe impacts on the water availability in semi-arid regions. In this study, we assessed the impact of climatic changes on water availability in the Altınapa Reservoir Watershed, located in the Konya province, south-central Turkey. Altınapa Reservoir supplies drinking water to Konya, a city of about 2 million population. We investigated possible changes in streamflow and reservoir storage over 2021–2098 under two representative concentration pathway scenarios (RCP4.5 and RCP8.5) developed based on GFDL-ESM2M, HadGEM2-ES, and MPI-ESM-MR global circulation models. We used a physically based model (SWAT-Soil and Water Assessment Tool) for understanding the hydrologic response of the basin to climatic changes. Results show that upward trends in air temperatures in the range of 0.01–0.04 °C/year and 0.005–0.06 °C/year are expected from 2021 to 2098 under the RCP4.5 and RCP8.5 scenarios, respectively. According to the HadGEM2-ES model, precipitation and streamflow would show a downward trend at a rate of 0.96 mm/year and 0.007 m³/s/year under the RCP4.5 scenario and at a rate of 1.62 mm/year and 0.01 m³/s/year under the RCP8.5 scenario, respectively. GFDL-ESM2M and MPI-ESM-MR models project upward trends in precipitation and streamflow under the RCP4.5 scenario (in the range of 0.64–1.28 mm/year and 0.0003–0.006 m³/s/year, respectively), and downward trends under the RCP8.5 scenario (in the range of 0.47–0.76 mm/year and 0.0015–0.003 m³/s/year, respectively). Reservoir storage is projected to increase slightly according to GFDL-ESM2M model and decrease according to the HadGEM2-ES, and MPI-ESM-MR models under both scenarios. Precipitation, streamflow, and reservoir storage predictions of GFDL-ESM2M and MPI-ESM-MR models are considerably lower than those observed in the basin in recent decades, showing that water resources will decrease in the future. The changes in water withdrawal patterns could cause further reductions in water availability. Good resilience to climate change can be achieved by a flexible water management system and by reducing water consumption and water losses in the watershed and from the reservoirs.
... Delft3D was applied to simulate the effects of climate and nutrient changes in the IJsselmeer. Beyşehir (TUR) SWAT Beyşehir DYRESM-CAEDYM, PROTECH, PCLake [31][32][33] IJsselmeer (NLD) None IJsselmeer DELFT-3D, HABITAT [19] Once calibrated and tested (Section 3.2), the models were run for a baseline period of 1981-2010 and then for a scenario period of 2031-2060. The difference in the mean flow and concentrations simulated for the scenario and baseline periods were used to derive percentage changes. ...
... Changes in discharge also tend to reduce the differences between scenarios, making lake loadings less variable than the concentrations. The exception is Beyşehir, where reductions in both river discharge and river concentration cause a large change in load ( Figures S3 and S5) [32]. The changes in river discharge in the Yläneenjoki, Hobøl, and Vltava are small (1-10%), which makes the input loads of P and N less variable than the concentrations (Figures S3-S5). ...
Article
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Recent studies have demonstrated that projected climate change will likely enhance nitrogen (N) and phosphorus (P) loss from farms and farmland, with the potential to worsen freshwater eutrophication. Here, we investigate the relative importance of the climate and land use drivers of nutrient loss in nine study catchments in Europe and a neighboring country (Turkey), ranging in area from 50 to 12,000 km2. The aim was to quantify whether planned large-scale, land use change aimed at N and P loss reduction would be effective given projected climate change. To this end, catchment-scale biophysical models were applied within a common framework to quantify the integrated effects of projected changes in climate, land use (including wastewater inputs), N deposition, and water use on river and lake water quantity and quality for the mid-21st century. The proposed land use changes were derived from catchment stakeholder workshops, and the assessment quantified changes in mean annual N and P concentrations and loads. At most of the sites, the projected effects of climate change alone on nutrient concentrations and loads were small, whilst land use changes had a larger effect and were of sufficient magnitude that, overall, a move to more environmentally focused farming achieved a reduction in N and P concentrations and loads despite projected climate change. However, at Beyşehir lake in Turkey, increased temperatures and lower precipitation reduced water flows considerably, making climate change, rather than more intensive nutrient usage, the greatest threat to the freshwater ecosystem. Individual site responses did however vary and were dependent on the balance of diffuse and point source inputs. Simulated lake chlorophyll-a changes were not generally proportional to changes in nutrient loading. Further work is required to accurately simulate the flow and water quality extremes and determine how reductions in freshwater N and P translate into an aquatic ecosystem response.
... In recent decades, changing temperature and precipitation regimes as a consequence of global climatic change have resulted in severe droughts in major watersheds and regional ecosystems around the world (Stone et al., 2002;Walthall et al., 2013). Although projected water availability across different regions does not follow a universally increasing (Jung and Chang, 2011) or decreasing pattern (Milly et al., 2005), in many areas a dramatic decrease in freshwater availability is expected by the end of this century (Ruiz et al., 2008;Gosling and Arnell, 2016;Bucak et al., 2017). At the same time, human population growth and increasing urbanism are projected to occur disproportionately in larger river basins (Dubois, 2011). ...
... Given that many large river basins are projected to face both declining water availability (Gosling and Arnell, 2016;Bucak et al., 2017) and growing societal demand for water (Flörke et al., 2018), our approach provides an example of integrating numerical projections and hydrologic model outputs within a climate scenario framework. Our main contribution lays in the combination of distributed hydrologic runoff and streamflow projections, fed with scenarios of CMIP-5 downscaled outputs, with county-level water demand to reach an assessment of the spatial patterns of future water stress across the Red River basin. ...
Article
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Study region: Red River Basin of the South, United States of America. Study focus: We investigated the projected changes in water availability and demand across the Red River to identify regions of potential future water stress. The VIC model was calibrated, validated and then run with ensemble forcing from regionally representative global circulation model (GCM) outputs. For different combinations of representative concentration pathways (RCPs) we evaluated the impacts of climate change on streamflows and water availability throughout the basin. To estimate future water demand, we integrated a series of sector-specific regression models fit to historical water usage per county. New hydrological insights for the region: Despite discrepancies among GCMs projections, all future scenarios include a strong west-east gradient in water availability. Joint consideration of projected water demand and availability reveals that the distribution of future hotspots of water stress is spatially patchy and generally driven by changes in water demand, rather than availability. These hotspots of future water stress highlight locations of potential water conflicts. Our approach is likely to be applicable to drought-prone river basins worldwide where the spatial patterns of future water availability differ from spatial patterns of future water demand.
... Through a simulation of anticipated changes in water level by coupling SWAT to a Support Vector Regression model in Lake Beyşehir, which is the largest Mediterranea freshwater lake, Bucak et al. (2017) concluded that changes in climate have a more significant effect on the lake hydrology compared to land use. They also concluded that the ongoing intense water extraction may cause shallow lakes in the Mediterranean region to experience dramatic drought stress and lose their ecological value in the near future. ...
... Salvetti et al. (2008) A dry weather scenario was simulated by the QUAL2E model and a wet weather scenario was simulated by the BASINS-SWAT model in order to assess the nitrogen loads source apportionment. SVR Bucak et al. (2017) SWAT model and ε-SVR (a Support Vector Regression model) were linked to simulate future changes in water levels. ...
Preprint
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The Soil and Water Assessment Tool (SWAT) is a well-established eco-hydrological model that has been extensively applied to watersheds across the globe. This work reviews over two decades (2002–2022) of SWAT studies conducted on Mediterranean watersheds. A total of 260 articles have been identified since the earliest documented use of the model in a Mediterranean catchment back in 2002; of which 62% were carried out in Greece, Italy, or Spain. SWAT applications increased significantly in recent years since 86% of the reviewed papers were published in the past decade. A major objective for most of the reviewed works was to check the applicability of SWAT to specific watersheds. A great number of publications included procedures of calibration and validation and reported performance results. SWAT applications in the Mediterranean region mainly cover water resources quantity and quality assessment and hydrologic and environmental impacts evaluation of land use and climate changes. Nevertheless, a tendency towards a multi-purpose use of SWAT is revealed. The numerous examples of SWAT combined with other tools and techniques outline the model's flexibility. Several studies performed constructive comparisons between Mediterranean watersheds' responses or compared SWAT to other models or methods. The effects of inputs on SWAT outputs and innovative model modifications and improvements were also the focus of some of the surveyed articles. However, a significant number of studies reported difficulties regarding data availability, as these are either scarce, have poor resolution or are not freely available. Therefore, it is highly recommended to identify and develop accurate model inputs and testing data to optimize the SWAT performance.
... The Mediterranean Basin is undergoing a warming trend with longer and warmer summers, an increase in the frequency and the severity of heat waves, changes in precipitation patterns and a reduction in rainfall amounts (Cramer et al., 2018). With significant gaps in the socio-economic levels among the Mediterranean countries, particularly between the North (Europe) and South (Africa), parallel with population growth and migration (WorldBank, 2017), increased water demand under conditions of decrease in water availability and quality (Bucak et al., 2017), ecosystems degradation (Coll et al., 2010) and increased risk for forest fires (Turco et al., 2014) -the vulnerability of the Mediterranean population to human health risks increases significantly. Since health impacts largely arise due to exposure and vulnerability, they are enhanced by climate change. ...
Article
The Mediterranean Basin is undergoing a warming trend with longer and warmer summers, an increase in the frequency and the severity of heat waves, changes in precipitation patterns and a reduction in rainfall amounts. In this unique populated region, which is characterized by significant gaps in the socio-economic levels particularly between the North (Europe) and South (Africa), parallel with population growth and migration, increased water demand and forest fires risk - the vulnerability of the Mediterranean population to human health risks increases significantly. Indeed, climatic changes impact the health of the Mediterranean population directly through extreme heat, drought or storms, or indirectly by changes in water availability, food provision and quality, air pollution and other stressors. The main health effects are related to extreme weather events (including extreme temperatures and floods), changes in the distribution of climate-sensitive diseases and changes in environmental and social conditions. The poorer countries, particularly in North Africa and the Levant, are at highest risk. Climate change affects the vulnerable sectors of the region, including an increasingly older population, with a larger percentage of those with chronic diseases, as well as poor people, which are therefore more susceptible to the effects of extreme temperatures. For those populations, a better surveillance and control systems are especially needed. In view of the climatic projections and the vulnerability of Mediterranean countries, climate change mitigation and adaptation become ever more imperative. It is important that prevention Health Action Plans will be implemented, particularly in those countries that currently have no prevention plans. Most adaptation measures are "win-win situation" from a health perspective, including reducing air pollution or providing shading solutions. Additionally, Mediterranean countries need to enhance cross-border collaboration, as adaptation to many of the health risks requires collaboration across borders and also across the different parts of the basin.
... The above trends can be observed in all of the four climate change models (scenario RCP 8.5) that were used. Similar findings with regard to the trends of the above parameters under different climate change models and scenarios were reported from many other researchers [67,68] for the Eastern Mediterranean region. ...
Article
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Lakes, either artificial or natural, are greatly important as a component in their catchments’ hydrology, but also as ecosystem service providers. However, due to climate change, they have begun to face numerous problems with their water quality and quantity. Furthermore, general circulation models (GCMs) show future climate change with a reduction in rainfall and increase in temperature. The aim of the current study is to present an application where GCMs and state-of-the-art hydrological modelling system MIKE SHE/MIKE 11 are combined for assessing the response of a Greek lake in terms of its water balance and water level under climate change. Four general circulation models (GCMs; GFDL-CM3, MIROC-ESM-CHEM, MIROC-ESM, IPSL-CM5A-LR) for the extreme climate change scenario of RCP8.5 were used in the basin of Lake Zazari in Greece as a case study. Results showed that, by keeping the irrigated demands (the main water user) unchanged in the future, the lake exhibited a lower water level for all GCMs, fluctuating from −0.70 to −1.8 m for the mean (min) water level and from −0.30 to −1.20 m for the mean (max) water level. Instead of the above and by preserving the amount of withdraw water n from the lake at a certain percentage of inflows, the irrigated area should be reduced from 54.1% to 64.05% depending on the circulation model.
... Parallel to global trends, some of the largest lakes in central Turkey (e.g. Burdur, Acıgöl, Seyfe) have shrunk (Ataol, 2010;Temiz and Durduran, 2016;Kıymaz, 2009), and some others (Akgöl, Akşehir) even wholly dried out in the last 30 years (Dursun, 2010;Ş ener et al., 2010;Çatal, 2015;Temiz and Erduran, 2016;Bucak et al., 2017;Dervişoglu et al., 2017). Debates are still ongoing as to whether climate change or anthropogenic impacts are more dominant in this dangerous trend (Jeppesen et al., 2015). ...
Article
Mogan and Eymir lakes are shallow wetlands which are potentially susceptible to global warming. Previous geological studies demonstrated several complete desiccation and shrinkage events in Lake Mogan since the 1800s. Archival records show at least three desiccation events in 1910, 1934 and 1938, and many severe shrinkages later. Here, the significance of climatic and anthropogenic drivers is still a subject of curiosity. The back-analysis of the hydrological data during the regulator intervention indicates that Lake Mogan would have dried out in 1974, and would have shrunk considerably in the years 2007/2008 and 2017/2018 if human intervention was not involved. Our lake budget analysis shows that, assuming no human intervention and stream recharge, the water level of both lakes would have dropped below the threshold level in less than a week by natural downstream discharge, and the remaining volume of the lakes would evaporate in less than two years. This fact indicates the benefits of regulators for the protection of the lakes. The meteorological and lake budget data suggest that the underlying climatic threat over the studied lakes is high frequency (sub-decadal) rainfall scarcity coupled with long-term (several decades) insolation increase but not slow, steady deterioration of the climatic parameters.
... Nowadays, it is a limited source, especially for Mediterranean countries that are presently experiencing water stress. [1][2][3] Water resources are not equally distributed in space and time, 4 and they are currently under pressure due to human activities and economic development. The progressive population growth has led, on the one hand, to an intensification of urbanization and to an expansion of both water supply and sanitation systems 5 ; on the other hand, it has caused an increase in the global food production in order to meet the demand of a growing population. ...
Chapter
Climate change is exacerbating the existing water scarcity issue in the Mediterranean area, leading to unprecedented pressure on water supply, especially in arid regions. Current changes and future scenarios all indicate significant and increasing water demand during the coming decades. Water demand is further aggravated by the population growth, which consequently increases demand for crops and agricultural products. The use of reclaimed water (RW) seems to be a promising alternative and valuable water resource, particularly for agriculture, which is currently the main user of renewable water resources. In addition to preserving freshwaters, the use of RW for irrigation would represent a source of nutrients, namely nitrogen, phosphorus, and other salts, which are necessary for the physiological growth of crops. For the Mediterranean area, it was possible to investigate on the significance of the RW use through the comparison of different data such as the total amount of generated wastewater, which represents the potential of using RW as an irrigation source, and irrigation water requirement, respectively. The analysis showed that the use of RW could significantly decrease the current pressure on total renewable water resources, and therefore help to face water scarcity and climate change issues. Nevertheless, for the Mediterranean area, there are still limiting elements such as the non-existence of a univocal regulatory framework on the use of RW for irrigation purposes as well as a lack of data on real quantities of wastewater that are safely treated, collected and generated.
... This is especially true for reservoir water availability and quality. Recent studies on climate change impacts have addressed water availability (quantity and quality) in combination with socio-economic conditions, including changes in land cover/use and water uses (regarding reservoirs: Garcıa-Ruiz et al., 2011;Milano et al., 2013;La Jeunesse et al., 2015;Sellami et al., 2015Sellami et al., , 2016Lutz et al., 2016;Nunes et al., 2017 and, regarding streams: Ludwig et al., 2010;Serpa et al., 2015;Carvalho-Santos et al., 2016;Bucak et al., 2017). Other studies have discussed potential management and conservation strategies (in the context of agricultural activities) for reducing soil degradation as well as water depletion under present-day (Rocha et al., 2015;Prosdocimi et al., 2016;Majone et al., 2016) and/or future climate conditions (Iglesias and Garrote, 2015;Garrote et al., 2015). ...
Article
Future climate for the Mediterranean climatic region is expected to bring an increase in temperatures, decrease in the precipitation quantity and shifts in the seasonal precipitation pattern. Although the impacts of climate change on water resources have been relatively well explored for the Mediterranean climatic region, the specific consequences for reservoirs and, in particular, water availability and irrigation issues have been less studied. The objective of this work is two-fold: (i) to assess the impacts of future climate changes on water resources availability, quality (focusing on phosphorus loads as this is the limiting nutrient for eutrophication) and irrigation needs for two multipurpose reservoirs in southern Portugal; (ii) to suggest climate change adaptation strategies, especially for the agricultural sector. To this end, the SWAT model was first calibrated against existing data on reservoir inflows as well as phosphorus loads. Then, SWAT was run with climate derived EURO-CORDEX models (RCA4/RACMO22E) for four periods (1970–2000, 2010–2040, 2040–2070 and 2070–2100). Water availability was analysed using the Water Exploitation Index (WEI) that was calculated for both reservoirs combining changes of inflows and irrigation requirements. The results indicated that climate change will negatively impact water availability in both reservoirs, especially under RCP8.5. In the case of the Monte Novo reservoir, future domestic water supply could be constrained by water quality problems related with phosphorus loads. For Vigia reservoir, the high water exploitation will lead to water scarcity problems, mainly as this reservoir on present-day conditions is restrictive on irrigation requirements. Adaptation strategies such as the implementation of high end technology (e.g. soil moisture and plant water stress probes, satellite imagery and drones to evaluate water stress – NDVI) as well as the renewal of the irrigation network and adequate crop selection can help attenuating the effects of climate change on the water resources in this region.
... The water level in lakes is expected to follow this event. For example, the largest Mediterranean lake in Turkey, Beyşehir, which is within the A. danfordi distribution range (Tok et al., 2009), may dry out by the 2040s if the current outflow regime does not change (Bucak et al., 2017). Most individuals in our study cluster at older ages ( Table 2). ...
Article
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The age and growth in two breeding populations of A. danfordi, inhabiting altitudes ranging from 678 m a.s.l. to 1200 m a.s.l. in Turkey, were investigated. The age differences between sexes were not statistically significant in either population. The mean age was calculated as 8.73 ± 2.12 and 8.33 ± 1.8 years in Kozan and 7.25 ± 1.58 and 5.78 ± 1.64 years in Saimbeyli for males and females, respectively. The age distributions of males did not statistically differ between populations, but females in Kozan were significantly older than those in Saimbeyli. The mean snout-vent length (SVL) difference between sexes was not significant in the Kozan population, whereas males were significantly longer than females in Saimbeyli. However, SVL was similar between the populations. Intersexual differences in body size were found to be male-biased for both populations. There was a positive and statistically significant relationship between SVL and age in both populations. This study examines the feasibility of the use of skeletochronology for A. danfordi. It also shows that these populations are getting older and this may endanger the future of A. danfordi in a warming world. Some life history parameters and population structures of A. danfordi are provided in this study but some questions still remain.
... The Mediterranean Basin is undergoing a warming trend with longer and warmer summers, an increase in the frequency and the severity of heat waves, changes in precipitation patterns and a reduction in rainfall amounts (Cramer et al., 2018). With significant gaps in the socio-economic levels among the Mediterranean countries, particularly between the North (Europe) and South (Africa), parallel with population growth and migration (WorldBank, 2017), increased water demand under conditions of decrease in water availability and quality (Bucak et al., 2017), ecosystems degradation (Coll et al., 2010) and increased risk for forest fires (Turco et al., 2014) -the vulnerability of the Mediterranean population to human health risks increases significantly. Since health impacts largely arise due to exposure and vulnerability, they are enhanced by climate change. ...
Article
The Mediterranean Basin is undergoing a warming trend with longer and warmer summers, an increase in the frequency and the severity of heat waves, changes in precipitation patterns and a reduction in rainfall amounts. In this unique populated region, which is characterized by significant gaps in the socioeconomic levels particularly between the North (Europe) and South (Africa), parallel with population growth and migration, increased water demand and forest fires risk-the vulnerability of the Mediterranean population to human health risks increases significantly. Indeed, climatic changes impact the health of the Mediterranean population directly through extreme heat, drought or storms, or indirectly by changes in water availability, food provision and quality, air pollution and other stressors. The main health effects are related to extreme weather events (including extreme temperatures and floods), changes in the distribution of climate-sensitive diseases and changes in environmental and social conditions. The poorer countries, particularly in North Africa and the Levant, are at highest risk. Climate change affects the vulnerable sectors of the region, including an increasingly older population, with a larger percentage of those with chronic diseases, as well as poor people, which are therefore more susceptible to the effects of extreme temperatures. For those populations, a better surveillance and control systems are especially needed. In view of the climatic projections and the vulnerability of Mediterranean countries, climate change mitigation and adaptation become ever more imperative. It is important that prevention Health Action Plans will be implemented , particularly in those countries that currently have no prevention plans. Most adaptation measures are "win-win situation" from a health perspective, including reducing air pollution or providing shading solutions. Additionally, Mediterranean countries need to enhance cross-border collaboration, as adaptation to many of the health risks requires collaboration across borders and also across the different parts of the basin.
... The consequences on the hydrological cycle of the observed and projected change in the precipitation and temperature regimes in the Mediterranean affect the whole ecosystem and, consequently, essential socio-economic activities, like drinking water distribution (UN, 2021;Maiolo et al., 2017), food production (FAO, 2016;Ronco et al., 2017) or preparedness to hydrometeorological extremes (Madsen et al., 2014). Therefore, in the last years, the climate change impact studies dealing with the projected hydrological variability in Mediterranean catchments has increased tremendously, addressing either the whole region (e.g., Hertig andTramblay, 2016, Hartmann et al., 2017) or smaller areas (e.g., Spain: Estrela et al., 2012;Majone et al., 2012;Olmos Giménez et al., 2016;France: Lafaysse et al., 2014;Prats et al., 2018;Dayon et al., 2018;northern Africa: Beyene et al., 2010;Sellami et al., 2016;Taïbi et al., 2019;Hadour et al., 2020;Greece: Tigkas et al., 2012;Koutroulis et al., 2013;Nerantzaki et al., 2020;Middle East: Smiatek et al., 2014;Bucak et al., 2017;Gorguner et al., 2019;Italy: Senatore et el., 2011;Ravazzani et al., 2015;Pumo et al., 2016;Majone et al., 2016;Perra et al., 2018;D'Oria et al., 2019;Peres et al., 2019;Citrini et al., 2020). ...
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Study region Crati River Basin, Southern Italy, Central Mediterranean. Study focus We evaluate the combined effect of multiple global and regional climate model (GCM-RCM) combinations and bias correction (BC) methods on the hydrological impact of projected climate change. Under the representative concentration pathway RCP4.5, 15 EURO-CORDEX members, combining 6 GCMs and five high-resolution (0.11°) RCMs, provide the meteorological input for a spatially distributed hydrological model. RCM-derived input data are uncorrected and corrected through three empirical methods, leading to 60 different simulations for three ~30-year future periods in 2020–2096, compared to the baseline 1975–2005. The combined uncertainty of the climate models and correction methods is evaluated for the main hydrological variables using an analysis of variance (ANOVA) method. New hydrological insights for the region Results highlight a considerable agreement in projecting a decreasing trend of available water resources (on average, −70 % for snow, −8 % for root zone soil moisture and −17 % for river runoff in the period 2070–2096), due to the remarkable mean temperature increase and less accentuated precipitation reduction. The uncertainty evaluation shows that (1) the primary source of uncertainty is the driving GCM, and (2) BC methods smooth the projected hydrological impact in a not negligible way, especially concerning discharge (for each future period, the reduction projected without bias correction is about 3 % higher than with BC), therefore contributing to the total uncertainty.
... The SWAT model has been tested in different sectors (e.g., agricultural water management, water scarcity, and water quality management) and discussed extensively in the literatures (Gassman et al., 2007). More recently SWAT model has been applied for improving drought management (Wu and Johnston, 2007;Zhang et al., 2007;Wang et al., 2011;Kamali et al., 2015;Bucak et al., 2017). ...
Article
Identification of thresholds associated with key climate, catchment and morphological variables for hydrological droughts can further improve our understanding of evolution and propagation of droughts in a complex water resource system. These thresholds are associated with complex interaction between climate and catchment variables and they are often connected through hierarchical as well as non-linear relationships. The advantage of selecting a multi-factor predictor domain can detect multiple thresholds that may not be observed by analyses limited to single predictors. In the present study, we developed a conceptual modeling framework by integrating a hydrological model developed based on the Soil and Water Assessment Tool (SWAT) and statistical models to quantify the potential influence of climate, catchment, and morphological variables and their thresholds on hydrological drought duration and severity for the watersheds located in Savannah River Basin (SRB). The concept of standardized runoff index (SRI) was used to derive the multiscale hydrological drought time series (i.e., SRI 1, SRI 6, and SRI 12) to investigate short term, medium term, and long term drought events based on their duration and severity. It was observed that the linear models developed based on the climate variables may not be capable for predicting the duration of multiscale hydrological droughts, whereas, the performance of statistical models can be significantly improved by the addition of catchment and morphological variables. In addition, among the morphological variables stream order seems to have a significant control over short, medium and long term drought duration across the study area. In the second phase of our analysis, we employed classification and regression tree (CART) algorithm for quantifying the thresholds associated with climate, catchment, and morphological variables that have potential influence on the hydrological drought. The result indicates that the variables and its associated threshold vary for short, medium, and long term drought. The proposed modeling framework can be extended for ungauged basins to improve the drought management.
... The impact of each modeled hydrologic scenario on regional water availability was determined using both the Regional Hydro-Ecologic Simulation Systems (RHESSys) model (Tague & Band, 2004) and the Soil and Water Assessment Tool (SWAT) model (Neitsch et al., 2011). Both models have been widely used for LULC change and climate change studies, with SWAT frequently applied for larger basins (Bucak et al., 2017;Du et al., 2013;Kim et al., 2013;Kim et al., 2017;Schilling et al., 2009;Yin et al., 2017) and RHESSys in small and medium size catchments where greater detail in the spatial pattern of land cover, vegetation, and infrastructure is required (Bart et al., 2016;Hwang et al., 2018;Martin et al., 2017;Shin et al., 2019;Zia et al., 2016). Additionally, RHESSys has been widely applied in simulation of spatially distributed surface and subsurface runoff, ET, carbon and nitrogen cycling, and soil moisture under various land use and climate change scenarios (e.g., Band et al., 1996;Bart et al., 2016;Garcia et al., 2016;Hanan et al., 2017;Hwang et al., 2009Hwang et al., , 2018Lin, 2013;Lin et al., 2015;Martin et al., 2017;Miles & Band, 2015;Tague & Band, 2004). ...
Article
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Climate and land cover change strongly shape water resources management, but understanding their joint impacts is extremely challenging. Consequently, there is limited research of their integrated effects on water supply systems, and even fewer studies that rigorously account for infrastructure investment and management interventions. We utilize ecohydrologic modeling to generate watershed outflows under scenarios of climate and land cover change, which in turn drive modeled water utility‐level decision making for the Research Triangle region of North Carolina. In the Triangle region, land cover and climate change are both likely to increase water supply availability (reservoir inflows) individually and in tandem. However, improvements from water supply increases are not uniform across management system performance indicators of reliability, conservation implementation frequency (i.e., water use restrictions), and infrastructure investment. Utility decisions influence the impact of hydrologic change through both short‐term (e.g., use restrictions and water transfers) and longer‐term infrastructure investment actions, in some cases offsetting the beneficial effects of additional water supply. Timing and sequencing of infrastructure development are strongly sensitive to climate and land use change as captured by their impacts on utility performance outcomes. This work underscores the need to consider adaptive management system responses and decision‐relevant performance measures when determining the impacts of hydrologic change on water availability.
... Groundwater inflows into streams play an important role in the ecological balance of streams, contributing chemicals that drive water quality [1][2][3][4][5], supporting baseflow [6][7][8][9][10][11] and providing refuge for fauna [12][13][14][15][16][17][18][19][20][21]. Locating and mapping inflows is thus of great interest for river management and ecological restoration [22][23][24][25][26]. ...
Article
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Although fiber optic distributed temperature sensing (FO-DTS) has been used in hydrology for the past 10 years to characterize groundwater–streamwater exchanges, it has not been widely applied since the entire annual hydrological cycle has rarely been considered. Properly distinguishing between diffuse and intermittent groundwater inflows requires longer periods (e.g., a few months, 1 year) since punctual changes can be lost over shorter periods. In this study, we collected a large amount of data over a one-year period using a 614 m long cable placed in a stream. We used a framework based on a set of hypotheses approach using thermal contrast between stream temperature and the atmosphere. For each subreach, thermal contrast was normalized using reference points assumed to lie outside of groundwater influence. The concepts and relations developed in this study provide a useful and simple methodology to analyze a large database of stream temperature at high spatial and temporal resolution over a one-year period using FO-DTS. Thus, the study highlighted the importance of streambed topography, since riffles and perched reaches had many fewer inflows than pools. Additionally, the spatial extent of groundwater inflows increased at some locations during high flow. The results were compared to the usual standard deviation of stream temperature calculated over an entire year. The two methods located the same inflows but differed in the mapping of their spatial extent. The temperatures obtained from FO-DTS open perspectives to understand spatial and temporal changes in interactions between groundwater and surface water.
... Probably, different results would be observed if a different climate scenario were assumed. Nevertheless, this estimate of SDI using climate model outputs is relevant and useful to get insight into surface water resources availability under the imminent fact of climate disturbance (Chattopadhyay et al. 2017;Bucak et al. 2017). ...
Article
In water resources and environmental management, hydrologic indexes are often valued as decision support tools because of their practical interpretability. This is true with the streamflow drought index (SDI), which is considered to be a relevant tool for assessing the availability of water resources at the watershed level. Hence, the future of freshwater resources at the watershed scale could be better understood by achieving a realistic projection of SDI. This study used a process-based watershed modeling approach to describe a framework for SDI projection. Specifically, the Soil and Water Assessment Tool (SWAT) model was used to simulate distinctly two watersheds located in the state of Texas, the Trinity and the Neches River Basins. The SWAT model was calibrated with monthly streamflow data for the period 1990–1995. The model was subsequently validated with two decades of discharge data (1996–2015). The evaluation of the SWAT performance during the calibration and validation stages showed acceptable values of efficiency criteria for both watersheds (i.e., Nash-Sutcliffe efficiency ranging from 0.56 to 0.65; index of agreement from 0.79 to 0.92). The calibrated model was used to simulate runoff for the future period 2041–2070 using inputs retrieved from a future climate scenario. However, the SDI calculation requires knowledge of the probability distribution of cumulative discharge data. A Kolmogorov-Smirnov’s goodness-of-fit analysis was conducted for both observed and simulated cumulative discharges. A lognormal distribution was considered for estimating time series of SDI. For the period 1996–2015, the SDI values recovered from the SWAT simulations matched closely with those derived directly from the observed discharge data (0.52≤R2≤0.91 for the Neches River, and 0.79≤R2≤0.89 for the Trinity River). This result demonstrated the capacity of the analytical procedure to capture and project realistically SDI signals. However, analysis of the χ2 statistic of the SDI patterns for the past and the future periods did not reveal any significant difference.
... The SWAT model (SWAT 2012, Revision 637) is a river basin scale catchment model originally reported by Arnold et al. (1998). It can be used to study the plausible impacts of LUCC and also different methods of land management on river water quality and quantity, and agricultural-chemical matters in drainage basins (Milano et al., 2013;Bucak et al., 2017). In SWAT, the drainage basin is further divided into subbasins using the DEM. ...
Article
The impact of land use and climate change (LUCC) on the pattern of groundwater and land subsidence at the Marand Plain was investigated in this study. Earth deformation was derived from ENVISAT ASAR (2003.12.17–2006.03.01) and Sentinel-1 (2015.05.03–2015.10.18) satellite data via the Synthetic Aperture Radar Interferometry (InSAR) small baseline subset (SBAS) time series analysis method. Time series analysis results showed the maximum deformation rate of 24 and 39 cm/yr extracted from ENVISAT ASAR and Sentinel-1, respectively. About 3141 ha of the plain area have been affected by the subsidence phenomenon, which has caused severe damage to constructions. Observed groundwater level (GWL) observed data, indicate a reduction of five meters on average for the period of 1997–2015. Linear regression was derived between GWL abatement and subsidence with average correlation coefficient of 0.73 and the rate of subsidence was about 2.6–8 cm for a one meter drop in the GWL. Owing to the obtained relations between GWL reduction and subsidence, the effects of LUCC on groundwater storage (GWS) variability, and consequently the plain subsidence was studied using the Soil and Water Assessment Tool (SWAT). Climate change scenarios were represented by the delta change approach based on the trend for the past three (1985–2014) and last decade (2005–2014), respectively by low delta change (LDC) and high delta change (HDC), where the trend of the most recent decade yield a higher delta change when extrapolating into 2030. After calibration and validation of the SWAT model using the monthly flow data, baseline (Sb) and five different LUCC scenarios (S1-S5) were simulated and their effects on the GWS variability were compared with together. The simulated results of Sb vs. S4 and S5, which represent plausible scenarios show that LUCC may decrease GWS about 52–99% and 85–100% under LDC and HDC, respectively. The results of the scenarios show the significant value of climate change (CC), under HDC, compared to land use change (LUC) in the diminishing of the GWS and as a result, the severe occurrence of the subsidence in the region.
... and quality (Section 3.1.3.5) (Bucak et al. 2017), ecosys-39 Parts of this chapter have been published by Linares et al. (2020). tem degradation (Section 4.3) (e.g., Coll et al. 2010) and increased risk of forest fires (Section 4.3.2.1) (e.g., Turco et al. 2014), the vulnerability of the Mediterranean population to human health risks is increasing significantly. ...
... Population increase, changes in land use and water demand were also important forces for the lake water level variations. Bucak et al. (2017) estimated the future levels of the Lake Beysehir in the Mediterranean region and influences of climate change and land use upon it by applying Soil and Water Assessment Tool (SWAT) model with a Support Vector Regression Model (SVR). The empirical results indicate that Mediterranean regions are in a high risk of freshwater loss caused by continuous climate changes and forecasted a 15-52% reduction in total flows by the end of the century. ...
Article
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Lake (or lacustrine) water is one of the most sensitive and vulnerable resources for many tourist destinations, whose attractiveness highly depends on the water quality and availability in the lakes. The Shchuchinsk-Burabay resort area, located in the Akmola region of the Northern Kazakhstan, is one of the most popular tourist destinations of the country, known for its attractive natural landscape and for its great number of lakes. However, during the last decades, these lakes have been facing environmental issues due to their overexploitation and increasing level of pollution. Thus, the aim of the current study is to examine the changes in surface area of these lakes during the last 30 years by using GIS technologies, and the influence of tourism industry upon this phenomenon. Accommodation facilities (hotels, sanatoriums and guesthouses), as main tourism-related water consumers, have been targeted within our analysis. Results show that tourism is one of the factors responsible for surface area decline of the main lakes in the region, and its responsibility increases when combined with other factors. This study also formulates recommendations for water management policymakers in order to guarantee the sustainability of lake water as a key resource of the tourism industry in the region.
... and quality (Section 3.1.3.5) (Bucak et al. 2017), ecosystem degradation (Section 4.3) (e.g., Coll et al. 2010) and increased risk of forest fires (Section 4.3.2.1) (e.g., Turco et al. 2014), the vulnerability of the Mediterranean population to human health risks is increasing significantly. ...
... This approach takes GCM or RGM outputs and uses this to force hydrological models in order to derive water balance components for watersheds such that the impacts of climate change on water resources can be investigated (Angelina, Gado Djibo, Seidou, Seidou Sanda, & Sittichok, 2015;Chattopadhyay & Jha, 2016;Ertürk et al., 2014;Fujihara et al., 2008;Stehr, Debels, Romero, & Alcayaga, 2008;Sunde et al., 2017;Zeng, Xia, She, Du, & Zhang, 2012). For example, Bucak et al. (2017) demonstrated the risk of drying of Beyşehir Lake due to climate change by using the SWAT hydrological model coupled with regional climate model outputs. However, outputs of General Circulation Models (GCMs) are often too spatially coarse to investigate hydrological impacts at many river basin scales. ...
Article
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Water resources in semi‐arid regions like the Mediterranean Basin are highly vulnerable because of the high variability of weather systems. Additionally, climate change is altering the timing and pattern of water availability in a region where growing populations are placing extra demands on water supplies. Importantly, how reservoirs and dams have an influence on the amount of water resources available is poorly quantified. Therefore, we examine the impact of reservoirs on water resources together with the impact of climate change in a semi‐arid Mediterranean catchment. We simulated the Susurluk basin (23.779‐km2) using the Soil and Water Assessment Tool (SWAT) model. We generate results for with (RSV) and without reservoirs (WRSV) scenarios. We run simulations for current and future conditions using dynamically downscaled outputs of the MPI‐ESM‐MR general circulation model under two greenhouse gas relative concentration pathways (RCPs) in order to reveal the coupled effect of reservoir and climate impacts. Water resources were then converted to their usages – blue water (water in aquifers and rivers), green water storage (water in the soil) and green water flow (water losses by evaporation and transpiration). The results demonstrate that all water resources except green water flow are projected to decrease under all RCPs compared to the reference period, both long‐term and at seasonal scales. However, while water scarcity is expected in the future, reservoir storage is shown to be adequate to overcome this problem. Nevertheless, reservoirs reduce the availability of water, particularly in soil moisture stores, which increases the potential for drought by reducing streamflow. Furthermore, reservoirs cause water losses through evaporation from their open surfaces. We conclude that pressures to protect society from economic damage by building reservoirs have a strong impact on the fluxes of watersheds. This is additional to the effect of climate change on water resources.
... Water temperature, directly influenced by air temperature, is expected to rise across different habitats [6]. Additionally, the occurrence of heatwaves will likely increase, resulting in extended periods of drought associated with a low flow of freshwater systems, a decrease in water level and in dissolved oxygen concentrations [7][8][9]. Consequently, reduced dilution of freshwater streams will also affect ion balance levels [10,11]. These biotic changes will impact ecosystem dynamics and promote disruptions in species equilibrium [9,12]. ...
Article
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Climate change is expected to create environmental disruptions that will impact a wide array of biota. Projections for freshwater ecosystems include severe alterations with gradients across geographical areas. Life traits in bacteria are modulated by environmental parameters, but there is still uncertainty regarding bacterial responses to changes caused by climatic alterations. In this study, we used a river water microcosm model to evaluate how Aeromonas spp., an important pathogenic and zoonotic genus ubiquitary in aquatic ecosystems, responds to environmental variations of temperature and pH as expected by future projections. Namely, we evaluated bacterial growth, biofilm production and antimicrobial resistance profiles of Aeromonas species in pure and mixed cultures. Biofilm production was significantly influenced by temperature and culture, while temperature and pH affected bacterial growth. Reversion of antimicrobial susceptibility status occurred in the majority of strains and tested antimicrobial compounds, with several combinations of temperature and pH contributing to this effect. Current results highlight the consequences that bacterial genus such as Aeromonas will experience with climatic alterations, specifically how their proliferation and virulence and phenotypic resistance expression will be modulated. Such information is fundamental to predict and prevent future outbreaks and deleterious effects that these bacterial species might have in human and animal populations.
... and quality (Section 3.1.3.5) (Bucak et al. 2017), ecosystem degradation (Section 4.3) (e.g., Coll et al. 2010) and increased risk of forest fires (Section 4.3.2.1) (e.g., Turco et al. 2014), the vulnerability of the Mediterranean population to human health risks is increasing significantly. ...
... and quality (Section 3.1.3.5) (Bucak et al. 2017), ecosys-39 Parts of this chapter have been published by Linares et al. (2020). tem degradation (Section 4.3) (e.g., Coll et al. 2010) and increased risk of forest fires (Section 4.3.2.1) (e.g., Turco et al. 2014), the vulnerability of the Mediterranean population to human health risks is increasing significantly. ...
... It remains challenging to quantitatively predict future lake volume changes, due to the lack of detailed information about regional lake watersheds and lack of numerical models that represent detailed lake dynamics and interactions with the environment. Water level changes of specific lakes have been projected based on observation-guided water budget analysis, indicating potential water level drop for Great Lakes 28 and substantial drying for the largest freshwater 43 and salt 44 lakes in the Mediterranean, which are consistent with our qualitative prediction shown in Fig. 1e, f. The projected lake changes under global warming may have already emerged in observations, which feature drying lakes in the Mediterranean 44,45 and expanding lakes in Tibetan Plateau 46 . ...
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Lakes are critical natural resources that are vulnerable to climate change. In a warmer climate, lake evaporation is projected to increase globally, but with substantial variation between regions. Here, based on ensemble projections of climate and lake models and an attribution method, we show that future lake evaporation increase is strongly modulated by regional hydroclimate change. Specifically, a drying hydroclimate will amplify evaporation increase by enlarging surface vapor pressure deficit and reducing cloud shortwave reflection. Future lake evaporation increase is amplified in tropical America, the Mediterranean and Southeast China with drier future hydroclimates, and dampened in high latitudes and the Tibetan Plateau with wetter future hydroclimates. Such spatially coupled changes in lake evaporation and hydroclimate have important implications on regional lake water balance and volume change, which can aggravate water scarcity and flood risks.
... Mediterranean climate regions have witnessed one of the most severe warming events in the world, and increases in the severity and longevity of droughts (Molina et al., 2020), threatening their sensitive endemic fauna and flora (Myers et al., 2000). Even though Mediterranean species are adapted to climatic fluctuations, climate change scenarios projected for the next decades will pose serious challenges to local wildlife (Bucchignani et al., 2018), particularly to freshwater organisms (Bucak et al., 2017). ...
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Lakes Volvi and Koronia are located in the Mygdonia basin and constitute the second and fifth largest natural lakes in Greece, respectively. The lakes along with the Mygdonia basin aquifer have undergone severe quantitative and qualitative degradation, while the Lake Koronia has been totally depleted in recent years. In this study, a fully integrated hydrological analysis of the Mygdonia basin for historical and future periods is carried out. Future climatic data were derived and analyzed from a Regional Climate Model, while the implications of climate change on water balance of both lakes and the Mygdonia basin aquifer until 2100 were projected by developing a modelling system which includes coupled hydrological and hydraulic models, such as UTHBAL, MIKE SHE, MIKE HYDRO River and the MIKE HYDRO Basin. The results indicated that the precipitation is expected to decrease by 17%, the temperature to increase by 2.90 °C and as a result, the surface runoff is projected to decrease by 21% and the groundwater recharge to decrease by 38% in the Mygdonia basin at the end of the century. The above changes would have a direct negative impact on the Lakes Koronia and Volvi and the Mygdonia basin aquifer future water balance necessitating adaptation measures.
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Ekonomik gelişmeler ile birlikte artan nüfus ve bununla birlikte iklim değişikliği tatlı su kaynakları üzerindeki baskıyı ve su kaynaklarına erişimdeki rekabeti her geçen gün artırmakta olup bu durumun gelecekte küresel ölçekte su krizlerine yol açması beklenmektedir. Hükümetlerarası İklim değişikliği Paneli'nin beşinci değerlendirme raporun farklı emisyon senaryoları için çalıştırılan küresel iklim modeli çıktıları Akdeniz Havzası'nda yirmi birinci yüzyıl sonlarına doğru sıcaklık artışları ile birlikte yağışlarda önemli ölçüde azalmalar görüleceğini vurgulamaktadır. Türkiye'nin de içerisinde yer aldığı Akdeniz Havzası'nın gelecekte küresel iklim değişikliğinden en fazla etkilenecek en kırılgan bölgelerden biri olacağı beklenmektedir. Yağış ve sıcaklıklardaki değişmelere paralel olarak, kişi başına düşen kullanılabilir su potansiyeli açısından hali hazırda su sıkıntısı çeken ülkeler arasında yer alan Türkiye'nin su kaynaklarının bu değişimlerden olumsuz yönde etkileneceği öngörülmektedir. Dünya genelinde ve Türkiye'de içme-kullanma amaçlı su tüketimi miktarı toplam tüketim içerisinde görece düşük bir yüzdeye sahip olmasına karşın başta büyük şehirler olmak üzere içme-kullanma suyu ihtiyacı çoğunlukla yüzeysel su kaynaklarından temin edilmektedir. İklim elemanlarının zamansal ve mekânsal ölçekteki değişimleri, şehirlerdeki hızlı nüfus ve su tüketim miktarı artışı ile birlikte arazi kullanımındaki değişimler içme-kullanma suyu ihtiyacın yüzeysel su kaynaklarından karşılanmasında güçlüklere neden olmaktadır. İklim koşullarındaki değişikliklerden doğrudan etkilenecek olan yüzeysel su kaynaklarını etkileyen hidroklimatik ve insan kaynaklı süreçleri dikkate alan dinamik yaklaşımlarla risk yönetiminin yapılması büyük önem taşımaktadır. İstanbul kayıtlı 15 milyon nüfusu ile Avrupa'nın en büyük şehri olmakla birlikte dünyanın en kalabalık şehirleri arasında yer almaktadır. Şehrin yaklaşık 3 milyon m3/gün olan ham su ihtiyacının neredeyse tamamı İstanbul ve civarında yer alan yüzeysel su kaynaklarından temin edilmektedir. İstanbul'un su ihtiyaçlarının güvenilir bir şekilde sağlanması ve olası kriz dönemlerinde karşılaşılabilecek risklerin en az seviyede tutulması önem taşımaktadır. Bu nedenle su kaynaklarının mevcut ve gelecekteki potansiyelinin matematiksel modeller aracılığı ile ortaya koyulması, su miktarının hem mekânsal hem de zamansal dağılımının iyi bilinmesi ve bunların şehrin gelecekteki su ihtiyaçları ile birlikte ele alınarak kapsamlı bir şekilde değerlendirilmesi gereklidir. Bu çalışmanın amacı İstanbul'un yüzeysel su kaynaklarının potansiyelini matematiksel modeller ile ortaya koymak, iklim değişikliğinin mevcut su kaynaklarına olası etkilerini araştırmak ve su temin sistemini su arz ve talepleri ile birlikte iklim değişikliği senaryoları altında incelemektir. Bu çalışma ayrıca İstanbul'un su kaynakları sisteminin etkin yönetimine yardımcı olabilecek, gelecekte yapılacak planlama ve risk yönetimi çalışmalarına yönelik modelleme altyapısının oluşturulması amacını da taşımaktadır. Bu kapsamda İstanbul'a içme-kullanma suyu temini amacı ile kullanılan havzaların su bütçesi bileşenleri hidrolojik proses modeli yardımı ile ortaya koyulmuştur. Hem referans dönem hem de gelecek yıllara ait su bütçesi ve akarsu debi tahminlerinde hidrolojik proses modeli olarak Soil and Water Assesment Tool (SWAT) modeli kullanılmıştır. Modelin kurulumunda küresel ve ücretsiz olarak elde edilebilen veri setlerinden yararlanılmıştır. Çalışma bölgesi için kurulan SWAT modeli, otomatik kalibrasyon ve belirsizlik analiz programı olan SWAT-CUP programı ile kalibre edilmiş, model kalibrasyonu ve belirsizlik analizi için program içerisinde yer alan SUFI2 algoritması kullanılmıştır. Model kalibrasyonunda çalışma bölgesi içerisinde yer alan ve Devlet Su İşleri (DSİ) tarafından işletilen 25 farklı akım gözlem istasyonuna ait akım rasatları kullanılmıştır. İklim değişikliğinin su kaynaklarına etkisinin araştırılmasında ihtiyaç duyulan yağış ve sıcaklık gibi iklim elemanları için küresel iklim modeli (GCM) çıktılarından yararlanılmıştır. Bu kapsamda GFDL-ESM2M, HadGEM2-ES, IPSL-CM5A-LR, MIROC ve NoerESM1-M olmak üzere beş farklı küresel iklim modelinin RCP 4.5 ve RCP 8.5 senaryolarına ait çıktıları istatiksel ölçek küçültme yöntemi ile çalışma bölgesine uyarlanarak değerlendirilmiştir. SWAT modeli referans dönem için 1977-2013 yılları için çalıştırılmış, iklim değişikliği projeksiyonları ise 2020-2099 yılları için gerçekleştirilmiştir. İstanbul'a içme-kullanma suyu temini amacı ile kullanılan rezervuarların su bütçelerine ilişkin simülasyonlar için Water Evaluation and Planning (WEAP) modeli kullanılmış. WEAP modeli, hidrolojik proses modelinden elde edilen su bütçesi bileşenleri, şehrin gelecekteki su ihtiyaçları ile birlikte rezervuarların fiziksel ve işletme verileri ile kurularak sistemin gelecekteki durumu ortaya koyulmuştur. Rezervuarlardaki su bütçesi simülasyonları 2020-2053 yılları için gerçekleştirilmiştir. Hidrolojik proses modeli çıktılarına göre Melen Havzası ile birlikte İstanbul'un 1980-2013 referans dönemi için toplam mavi su potansiyeli 3.5 m3/yıl, yeşil su akışı 2.9 m3/yıl ve yeşil su deposu 0.9 milyar m3/yıl olarak belirlenmiştir. Şehrin yüzeysel akışa geçen ve dolayısıyla baraj göllerini besleyen toplam su potansiyelinin %75'ini (~2.6 milyar m3/yıl) Asya bölgesinde yer alan su kaynakları oluşturmaktadır. Melen Havzası yıllık 1.5 milyar m3'lük su potansiyeli ile sistemin yaklaşık %45'lik kısmını oluşturmaktadır ve İstanbul için önemli bir su kaynağı konumundadır. Beş farklı küresel iklim modeli ve iki farklı senaryo için yapılan gelecek dönem projeksiyonlarına ilişkin sonuçlar iklim modellerinin toplu değerlendirilerek sunulmuştur. Buna göre İstanbul'un mavi su potansiyeli RCP 4.5 senaryosuna göre yakın dönemde (2020-2050) %2, uzak dönemde (2070-2099) ise %12 mertebelerinde ve RCP 8.5 senaryosuna göre yakın dönemde (2020-2050) %12, uzak dönemde (2070-2099) ise %28 mertebelerinde azalacağı öngörülmektedir. Modelleme çalışmalarında İstanbul'a içme suyu temin edilen baraj göllerine ulaşan toplam akım değerinin referans dönem için ortalama değeri 108 m3/s olarak hesaplanmış, iklim projeksiyonlarına göre yakın dönemde her iki senaryo için benzer azalma miktarı elde edilmiş, (RCP 4.5 için %12 azalma ve RCP 8.5 için %15 azalma) uzak döneme ait sonuçlarda ise RCP 4.5 senaryosuna göre baraj göllerine ulaşan toplam akış miktarı %19 oranında azalırken, bu azalmanın RCP 8.5 senaryosuna göre %30 civarında olacağı öngörülmüştür. Modelleme çalışmaları ve gözlem sonuçları değerlendirilerek hidrolojik kuraklığın etkisinin hissedilmeye başlandığı referans dönem değeri 90 m3/s olarak belirlenmiş, RCP 4.5 ve RCP 8.5 senaryoları için yapılan projeksiyonlarda sistemde 2050'li yılların sonuna kadar bu eşik değerin görülme sıklığı ve şiddetinde önemli bir değişiklik görülmemiştir. 2060'ların başından itibaren ise belirlenen hidrolojik kuraklık eşik değerinin görülme sıklığı ve şiddetinde önemli ölçüde artışlar görülmekte olup aynı zamanda su eksikliğinin görüldüğü ardışık yılların sayısının da artması beklenmektedir. Su bütçesi simülasyonları Melen Baraj'ının devreye alınmaması yalnızca regülatörden su transferinin gerçekleşmesi durumunda İstanbul'un içme-kullanma su ihtiyacının karşılanmasında 2030'ların başından itibaren güçlüklerin olabileceğini göstermektedir. Melen Baraj'ının tamamlanması ile birlikte toplam su depolama kapasitesi önemli ölçüde artan su temini sistemi 2070 yılına kadar şehrin su ihtiyaçlarını karşılayabilecek potansiyele ulaşmaktadır. Dinamik modelleme yaklaşımları su kaynakları sistemlerinin değerlendirilmesinde, havza yönetim ve planlamalarında kullanılan en etkin araçlardan biridir. Bu çalışma kapsamında geliştirilen su kaynakları modelleme altyapısı İstanbul'un su kaynakları sisteminin mevcut durumunun analizinin yapılmasına olanak sağlamış, aynı zamanda iklim değişiminin olası etkilerinin incelenmesine yardımcı olmuştur. Bu altyapı diğer su kaynakları sistemlerinin değerlendirilmesinde farklı amaçlara göre zenginleştirilerek uygulanabilir.
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Regional climates are the complex outcome of local physical processes and the non-local responses to large-scale phenomena such as the El Niño-Southern Oscillation (ENSO) and other dominant modes of climate variability. The dynamics of regional climates are determined by local weather systems that control the net transport of heat, moisture and momentum into a region. Regional climate is interpreted in the widest sense to mean the whole joint probability distribution of climate variables for a region including the time mean state, the variance and co-variance and the extremes. This chapter assesses the physical basis of future regional climate change in the context of changes in the following types of phenomena: monsoons and tropical convergence zones, large-scale modes of climate variability and tropical and extratropical cyclones. Assessment of future changes in these phenomena is based on climate model projections (e.g., the Coupled Model Intercomparison Project Phase 3 (CMIP3) and CMIP5 multi-model ensembles described in Chapter 12) and an understanding of how well such models represent the key processes in these phenomena. More generic processes relevant to regional climate change, such as thermodynamic processes and land–atmosphere feedback processes, are assessed in Chapter 12. Local processes such as snow–albedo feedback, moisture feedbacks due to local vegetation, effects of steep complex terrain etc. can be important for changes but are in general beyond the scope of this chapter. The main focus here is on large-scale atmospheric phenomena rather than more local feedback processes or impacts such as floods and droughts. Sections 14.1.1 to 14.1.3 introduce the three main classes of phenomena addressed in this Assessment and then Section 14.1.4 summarizes their main impacts on precipitation and surface temperature. Specific climate phenomena are then addressed in Sections 14.2 to 14.7, which build on key findings from the Fourth Assessment Report, AR4 (IPCC, 2007a), and provide an assessment of process understanding and how well models simulate the phenomenon and an assessment of future projections for the phenomena. In Section 14.8, future regional climate changes are assessed, and where possible, interpreted in terms of future changes in phenomena. In particular, the relevance of the various phenomena addressed in this chapter for future climate change in the regions covered in Annex I are emphasized. The regions are those defined in previous regional climate change assessments (IPCC, 2007a, 2007b, 2012). Regional Climate Models (RCMs) and other downscaling tools required for local impact assessments are assessed in Section 9.6 and results from these studies are used where such supporting information adds additional relevant details to the assessment. 14.1.1 Monsoons and Tropical Convergence Zones The major monsoon systems are associated with the seasonal movement of convergence zones over land, leading to profound seasonal changes in local hydrological cycles. Section 14.2 assesses current understanding of monsoonal behaviour in the present and future climate, how monsoon characteristics are influenced by the large-scale tropical modes of variability and their potential changes and how the monsoons in turn affect regional extremes. Convergence zones over the tropical oceans not only play a fundamental role in determining regional climates but also influence the global atmospheric circulation. Section 14.3 presents an assessment of these and other important tropical phenomena.