Many high temperature geothermal fields generally occur at settings of recent active tectonism or volcanism accompanied by the active faults and fractures. It is well known that the structural controls such as topography, active faults, etc., have a major effect on fluid flow pathways in those systems. In this paper, a complete hydrothermo-geophysical model is created for the first time in the Gediz Graben, Western Anatolia. The finite volume method is used for numerical simulations by implementing a finite volume code, ANSYS-Fluent. The thermal and physical rock properties used in the model are taken from previous studies. Fluid flow velocity vectors and resulted temperature patterns for the region are calculated and presented. Our simulations demonstrate that the low-angle Master Graben Boundary Fault (MGBF) has three dominant roles 1) transporting the meteoric water to the depths; 2) distributing the heated geothermal water into the basin with inner basin faults, 3) transmitting the heated water to the surface. The model in this work can be easily adopted and extended to explore the possible reservoir structures in other geothermal areas.