Hydrogeological model of the e-sector of Afşin-Elbistan coal basin

Hydrogeological characterization of E sector which is located at Elbistan coalfield and planned to be operated, was studied within the scope of thesis. The aim of the study is the development of the hydrogeological conceptual model of the site and validate the conceptual setting with mathematical groundwater flow model. In order to have the conceptual model, geological model was constructed by 700 borehole logs. Interrelations among the groundwater bearing units were characterized by means of geological model. Hydrogeological characteristics of groundwater bearing units were determined by isotope analysis, pump tests and groundwater level measurements. Afterwards, conceptual model of Elbistan-E Sector Coal Field was developed. The conceptual model was tested through numerical modelling using FEFLOW software. According to conceptual model of E sector, Pliocene - Pleistocene aged coal and gyttja units are bounded by the top and bottom by impervious clay layers. Hydraulic relations between carbonate rocks at the east of the Site and gyttja/coal layers are controlled by less permeable Kemaliye formation. Model calibration under steady state conditions was performed by using groundwater levels while transient conditions was performed by using drawdown/time curves data of pump tests. Average of the differences between measured and calculated values (RMS) are evaluated as approximately 4 meters during steady state calibration phase. Representative groundwater flow model was obtained. Sensitivity analysis was performed within the scope of work and uncertainties were determined. Results show that hydraulic conductivity and transfer rate which is one of the key parameters of boundary condition are sensitive parameters of the system. In order to eliminate this condition, more pumping tests on different locations should be carried out. The wells located at carbonated rocks which are mainly controlling the system and surrounding the E sector are not sufficient. Beside the similar projects already performed on the field, it is highly recommended to conduct a comprehensive hydrogeological study for Afşin-Elbistan basin. Keywords: Hydrogeology, conceptual model, groundwater flow model, hydrogeological model, numerical model