Roles of hydrogeochemical evaluations in estimating protection zones of Koc ¸pınar springs in Aksaray, central Anatolia, Turkey H. Elhatip Æ M.Af¸sin Abstract The present study indicates estimation of protection zones of Koc ¸pınar springs in Aksaray area by means of hydrogeochemical methods. Rele- vant hydrogeochemical studies were carried out to achieve this objective. Koc ¸pınar springs emerge on strike-slip Hasandag ˘ ı fault set (HFS) along the Tuzgo ¨lu ¨ (Salt Lake) fault zone (TFZ) in central An- atolia. The outcrops of volcanic origin exhibit dif- ferent hydrogeological properties in the study area. The hydrogeochemical evaluations of Koc ¸pınar springs represent good results about the available main groundwater flow systems that exist in this area. Marbles of Palaeozoic age form the main aquifer that recharges Koc ¸pınar springs. The CO 2 gas content of the spring waters is significantly high. Based on the ion concentrations, the water of this spring has mainly two hydrochemical facies: Ca– Mg–HCO 3 and Na–HCO 3 . Although, the hydro- chemical analyses showed that waters of these springs meet the drinking and irrigation water standards, the area around the springs is continu- ously being contaminated by both domestic and agricultural wastes. Therefore, detailed hydrogeo- logical, hydrochemical and isotopic investigations were carried out to accurately estimate the protec- tion zones of Koc ¸pınar springs. These studies showed that three main protection zones could be proposed against external pollution effects around the spring’s area. Keywords Hydrochemical facies Æ Koc ¸pınar springs Æ Protection zones Æ Tuzgo ¨lu ¨ (Salt Lake) Fault Introduction Koc ¸pınar springs are located to the north of Hasandag ˘, 28 km from Aksaray city (Fig. 1). Most of the previous studies deal with the geology and geomorphology of Koc ¸pınar region and its vicinity (Toprak and Go ¨ncu ¨og ˘lu 1993). There are many cold and thermal-mineral springs along Tuzgo ¨lu ¨ Fault Zone (TFZ), which was described in previous studies as a strike-slip and active fault (Sarog ˘lu and others 1987). The present paper indicates the results of hydrochemical and bacteriological evaluations of Koc ¸pınar springs that discharge along Hasandag ˘ ı Fault Set (HFS). Because the discharges of Koc ¸pınar springs are controlled by the above-mentioned structural features. The present study focused on the evaluation of structural, geohydro- logical, hydrogeochemical and bacteriologic properties of the springs for identifying the main protection zones that could be proposed against the external pollution effects in the study area. Physical and chemical parameters of the Koc ¸pınar spring waters were measured in the field and laboratory. Meanwhile, temperature, pH value, discharge volume and CO 2 gas of the spring-waters were measured during the field observations. Hydrochemical and isotopic analyses of the Koc ¸pınar spring waters were carried out four times during 1996–1998 to follow the seasonal facies changes. Hydrogeochemical aspects of Koc ¸pınar springs Geological studies In the study area, volcanics form an important link along the Neogene–Quaternary volcanic chain that developed on the Anatolian massive and Taurids running parallel to the Taurid mountain belt axis (Fig. 2). Most of the volcanic outcrops exist locally in association with fluviatile and lacustrine sediments. In the vicinity of Koc ¸pınar springs Received: 26 June 2000 / Accepted: 13 November 2000 Published online: 19 April 2001 ª Springer-Verlag 2001 H. Elhatip (&) Nig ˘de University, Aksaray Engineering Faculty, Environmental Engineering Dept., 68100 Aksaray, Turkey E-mail: elhatip@superonline.com Tel.: +90-382-2150953 Fax: +90-382-2150592 M. Af¸ sin Nig ˘de University, Aksaray Engineering Faculty, Geological Engineering Dept., 68100 Aksaray, Turkey Cases and solutions 1010 Environmental Geology (2001) 40:1010–1016 DOI. 10.1007/s002540100291