Evaluating of the hydrothermal groundwater flow of El Hamma shallow geothermal aquifer (South-eastern of Tunisia)

The area of El Hamma, southeast of Tunisia, is characterized by warm groundwater. The aquifer in the city of El Hamma is considered the main source of water to meet the needs of agricultural, industrial, domestic, and traditional baths. Nowadays, groundwater flow in the aquifer system and the thermal origin have been not well explained. The objective of this study is to develop a conceptual model of the geothermal groundwater flow path based on the temperature distribution in the aquifer in the study area.The groundwater temperature data was collected from 130 wells and implemented into a database. The sampled wells depth range between 25 and 80 m below ground level at temperatures between 18 and 65 degrees Celsius. The temperature remains constant throughout the year, regardless of the external climatic conditions. The variographic analysis and ordinary kriging techniques were used to map the spatial distribution of temperature in the study area. The conceptual model, hydrodynamic, geological, and thermal data confirm a vertical communication between the deep continental intercalary aquifer and the shallow Senonian aquifer through a system of vertical faults, the most important of which are the F1 fault in the west of the region, the F2 near Wadi El Hamma and the F7 towards the east.