Hydrogeological investigation of south-southwestern of Celikhan (Adiyaman) district

The aim of this study is to evaluate the hydrogeological and hydrogeochemical sources of Mir, Zerban, Havşari, Çokpınar and Balıksarı, which are used in the supply of drinking water in Adıyaman, in the Çelikhan Plain, which is under the influence of active tectonism and rich in high flow resources. The formation mechanisms of the springs were explained and, the discharge amounts of the resources in the real regime were calculated by evaluating the long-term flow measurements within the hydrogeological studies. The relationship between the chemical compositions of the waters and lithology was explained and their suitability for drinking and agricultural irrigation was examined by the hydrogeochemical studies. The pH, temperature (T) and electrical conductivity (EC) measurements of the waters were made in situ in the field. Major anion and cation analyzes of the waters were made in the present study. The units outcropping in the Celikhan plain and its surroundings are in the Paleozoic-Quaternary age range, and from the oldest to the youngest, Malatya Metamorphics, Koçali Complex, Mineral Complex and Plio-Quaternary alluviums are present. Recrystallized limestones belonging to Devonian-Jurassic Malatya Metamorphics cropping out in a wide area in the study area are the aquifer units of the springs. The dominant strike-slip fault systems in the region have been effective in the formation of the springs in the study area. The schist unit of the Malatya Metamorphites is the impermeable basement of the aquifer. Flow rates of the springs are high due to the width of the recharge area of the aquifer unit and also due to the karstification, secondary porosity and permeability in the unit. The pH values of the investigated waters vary between 7.56 and 8.9, the temperature (T) values vary between 9.7-11.9 ⁰C and the EC values between 119.80-278.30 μS/cm. The pHs of spring waters are generally in the basic character. They are suitable for drinking purposes according to TS, 266 and WHO drinking water standards. Mir, Zerban and Havşari springs are in Ca-Mg-HCO₃, and Çokpınar and Balıksırtı springs are in Ca-HCO₃ water type on the Piper diagram. The waters are suitable for all kinds of agriculture. The storage capacity (V) of Zerban Spring above the discharge level in the real regime between 14.01.2018 and 18.12.2018 is calculated 2.5*10⁶ m³. The storage capacity (V) of Havşari Spring above the discharge level in the real regime between 14.01.2010 and 16.12.2010 is calculated 3.9*10⁶ m³. And, the storage capacity (V) of Balıksırtı Spring above the discharge level in the real regime between 14.01.2010 and 10.01.2011 is calculated 2.5*10⁶ m³. Adıyaman city center provide drinking water from these springs. The total number of days sufficient for the population (310,644) of Adıyaman city was determined as 132 days in the dry period. Since the aquifer recharge area of the Zerban and Havşari springs is large, their flow rates are high, while the feeding area of the Balıksırtı Spring is narrow and many wells are drilled around it, the flow rates are low compared to other sources. In order to get better efficiency from the sources in dry periods, it is necessary to protect the recharge areas, to license the wells to be drilled in the plain in a controlled manner and not to draw too much water from these wells. When the NH₄⁺, NO₃⁻ and NO₂⁻ contents of the analyzed waters are examined, it is seen that they are below the standard values specified by the Turkish Standards Institute (TS, 266), however, waters with numbers K-3, K-5 and K-9 are higher than other waters. NO3- detected in high concentrations is thought to be related to animal grazing in the aquifer recharge zone, chemical fertilizers used in agricultural lands, animal wastes stored in the open on the land surface and septic fosses present on the recharge zones.