The hydrogeological investigation of Kozluk spring (Malatya)

The aim of this study, which is about the hydrogeological investigation of Kozluk Spring (Malatya), is to explain the formation of the springs, to determine the real regime periods with regular flow measurements, to explain the relationship between the chemical compositions of the waters with lithology, to determine the origins of the waters with chemical analyzes and isotope analyses. In addition, within the scope of this study, the chemical compositions of the waters were compared with various standards and their use for drinking purposes was evaluated. Groundwater samples were taken in May (2020) and September (2019) to represent the rainy and dry period. In both periods, chemical and isotope analyzes of groundwater were carried out. The pH, temperature (T) and electrical conductivity (EC) were measured in situ in the field while samples were taken from groundwater. The flow rates of the springs were measured with the help of rectangular weirs and the flow rates of the fountains were measured with the specific volume method. In the study area, recrystallized limestones and schists of Devonian-Jurassic Malatya Metamorphics crop out in large areas. The aquifer unit of the springs are recrystallized limestones and the impermeable basement unit of the aquifer is schists belonging to Malatya Metamorphics. The pH values of the examined waters vary between 7.30-8.04, the electrical conductivity values vary between 233.60-535.00 µS/cm. When the Schoeller diagram was examined, it was observed that the dominant cation in the groundwaters was Ca+2 and the dominant anion was HCO3-. In the Piper diagram, groundwater is in the CaCO3- and MgCO3- groups. The waters are of meteoric origin according to their δ18O and δ2H contents. According to their tritium contents, some of the waters are deep circulated and some are shallow circulated. It has been calculated that the total water storage capacity (VT) of Kozluk Spring and other springs above the discharge level in the real regime is 172x103 m3 and the discharge coefficients vary between 0.0058 and 0.057 day-1. It has been determined that laminar flow is dominant in the periods when the flow is low in the source, while turbulent flow is dominant in the periods when the flow is high. When the major anion, cation, metal analysis, NO2-, NO3-, NH4+, PO4-3 contents of the waters were compared with the TSE, 266 and WHO drinking water standards, it was determined that the waters were suitable for drinking in general. NH4+, NO3- and e-coli contents detected in some waters close to or above drinking water standards are caused by the direct outdoor storage of artificial and natural fertilizers used in agriculture, especially in summer months and from septic tanks. In order to maintain the groundwater quality in recrystallized limestone aquifers where surface karstification is also intense, less chemical and animal fertilizers should be used in agricultural activities on these lithological units and animal manures should be stored by creating impermeable levels (on impermeable concrete surfaces or thick impermeable linoleum).