|TITLE||PREDICTING THE EFFECTS OF CLIMATE CHANGE AND LAND USE ON LAKE BEYşEHIR AND ITS CATCHMENT|
|AUTHORS||Tuba Bucak (1)|Dennis Trolle (2)|Hans E. Andersen (2)|Hans Thodsen (2)|J. Alex Elliott (3)|Seyda Erdogan (1)|Ayse Idil Cakiroglu (1)|Meryem Beklioglu (1,4)|
- Department of Biological Sciences, Limnology Laboratory, Middle East Technical University, Ankara, Turkey
- Department of Bioscience, Aarhus University, Silkeborg, Denmark
- Center for Ecology and Hydrology, Algal Modelling Unit, Lake Ecosystem Group, Lancaster, United Kingdom
- Kemal Kurdas Ecological Research and Training Station, Middle East Technical University, Ankara, Turkey
|ABSTRACT||Lake Beyşehir is the largest freshwater lake in Turkey and is the main water supply for irrigation in the Konya Closed Basin, which is characterized by extensive agricultural practices in this semi-dry Mediterranean climate. Hence, the lake has been subjected to intensive anthropogenic stresses of excessive water withdrawals for irrigation and a dramatic decrease in water level especially during the drought periods. Climate change projections also suggest that air temperatures will increase while precipitation will decrease, which may also affect the hydrological regime and have further detrimental effects on the water quality of Lake Beyşehir.
In this study, we applied the catchment model SWAT (Soil and Water Assessment Tool), to evaluate the effects of potential land use changes and the projected future climate on water and nutrient runoff to Lake Beyşehir Climate change scenarios were based on IPCC A1B scenario derived from 3 regional climate models (ECHAM5-KNMI, HadRM3P-HadCM3Q0 and SMHIRCA-BMC) for 2031-2060. Outputs of SWAT (projections of future flow and nutrient loads) and outputs of the climate models were subsequently used as input to three individual lake ecosystem models (PCLake, DYRESM-CAEDYM, PROTECH), which provided an ensemble of projections of the future trophic state of Lake Beyşehir with special emphasis on chlorophyll a levels. The simulations suggest that future climate change in combination with a series of generated land use scenarios will have a major impact on the hydrology and nutrient loads. Hence, annual average surface run off was projected to decrease by up to 30%, and nitrogen and phosphorus loads by 39-63%, respectively. However, the projected impacts of these changes on lake productivity were minor, likely as the lake is already in a nutrient poor state. These results show that hydrological regime of Lake Beyşehir may go dramatical changes under future climate change and possible adaptation strategies should be developed for efficient use of water within Konya closed basin.|