The Thermal-Hydraulic-Chemical (THC) Prognostic Modelling project is focused on improving comprehension and control of geothermal resources. THC-Prognos aims to enhance the effectiveness and sustainability of geothermal energy extraction by utilizing sophisticated modeling techniques using extensive hydrochemical data from all over Germany to guarantee a dependable and eco-friendly energy supply for the future. The LIAG Institute for Applied Geophysics is essential to the THC-Prognos project, specifically in Part C, where it is responsible for incorporating comprehensive hydrochemical data into the Geothermal Information System (GeotIS). The responsibility of LIAG is to collect and verify hydrochemical data from different sources, such as existing databases, publications, and project partners. Subsequently, this data is analyzed and integrated into GeotIS, so creating a comprehensive database that can be accessed by researchers and industry professionals thus improving the usefulness and accessibility of hydrochemical data that facilitates more effective planning and management of geothermal resources. The anticipated results of the THC-Prognos project are diverse, encompassing refined prognostic models for geothermal systems, more data availability via GeotIS, and more informed decision-making about geothermal energy production. The project is a collaboration that involves multiple partners, each providing their specialized knowledge to different facets of the project.