Vol.:(0123456789) 1 3 Carbonates and Evaporites https://doi.org/10.1007/s13146-018-0418-1 ORIGINAL ARTICLE Surface runof and carbonates‑based defnition of protection zones for Egirdir Lake in western Turkey Muhterem Demiroglu 1  · Remzi Karaguzel 1  · Mahmut Mutluturk 2  · Cenk Yaltirak 1  · Tolga Yalcin 1  · Asli Donertas 3  · Aysen Davraz 2  · Zeynep Aktuna 1 Accepted: 30 December 2017 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Freshwater of Isparta and Egirdir is supplied from the Egirdir Lake, which is the second largest freshwater lake of the Lakes District in Western Turkey. The Egirdir Lake has been studied within the framework of the Basin Protection Plan Special Provisions of the Egirdir Lake. The impact of runof is taken into account in determining protection zones of the surface water reservoirs in Turkey. An approach that emphasizes the impact of groundwater fow in addition to the surface runof has been adopted in this study. Water in Lake Egirdir is often classifed as the Class II water according to terrestrial water resources quality criteria in Water Pollution Control Regulation of Turkey. The geological and hydrogeological studies reveal a signifcant amount of groundwater recharge into the Egirdir Lake through carbonate rocks and alluvial deposits outcropping in the basin, which is why Egirdir Lake still has a less contaminated water quality in spite of heavy pollutants. For this purpose, groundwater fow is prominently used in defning protection zones and surface runof as well. The inner protection zone, which is defned as the 50-day travel time, and the outer protection zone, defned as the 400-day travel time, were estimated by infltrometer and pumping tests in alluvium. Pumping tests results were used for the determination of hydraulic conductivities and groundwater levels for the determination of hydraulic gradients. Protection zones in karstic areas are based on the vulnerability map and large karstic springs. Keywords Egirdir Lake · Groundwater · Protection zone · Travel time Introduction Freshwater for the town of Isparta and the Egirdir district in Western Turkey, which amount of 30 hm 3 /year is supplied from the Egirdir Lake as well as 335 hm 3 /year for irriga- tion (IPDEU 2013). The Egirdir Lake with a water level of 917 m, 482 km 2 surface area, 6–7 m average depth, is a tectonic lake which has about 4 billion m 3 of water potential. The Egirdir Lake is being rapidly polluted due to a variety of activities carried out in the Egirdir Lake watershed. Point pollutants such as urban waste water, urban solid waste, industrial pollution loads and difuse pollutants such as agri- cultural fertilizers, pesticides, animal waste and leakages are discharged into the rivers that recharge the lake. Domestic wastes of towns surrounding the lake are discharged into the rivers without proper treatment. Main leather processing and rose oil production are the most important and environmen- tally risky activities in the lake area. The use of pesticides and chemical fertilizers in agriculture create additional pol- lutant sources. As a result, the current operational status of the lake (drinking water supply, irrigation, fsheries produc- tion, and recreational use) is adversely afected (Beyhan and Kacikoc 2008; Sener 2010; Sener et al. 2013; Bulut et al. 2016). Up to now, maximum beneft has been achieved from the lake; however, measures taken have not been able to pro- tect the lake from being contaminated. For this aim, protec- tion zones of the lake should be defned properly. Given the growing population and inevitable demands for changing land use, protection zones should be as large as necessary and as small as possible (Alfoldi 1986; Kacaroglu 1999). * Muhterem Demiroglu demiroglum@itu.edu.tr 1 Department of Geological Engineering, Istanbul Technical University, Istanbul, Turkey 2 Department of Geological Engineering, Suleyman Demirel University, Isparta, Turkey 3 TUBITAK-MAM, Environment Institute (CE), Istanbul, Turkey