Geological and hydrogeological studies in the selection of underground dam site: Pozantı-Yukarıbelemedik (Adana) sample project

The aim of the thesis is to examine the engineering geology of the axis location and storage area of the Yukarıbelemedik underground dam project, which is selected as a case study for the underground dam on the Karaçay stream located in the vicinity of Pozantı-Yukarıbelemedik, the hydrogeological characteristics, the determination of the levels that can be aquifers and the determination of the necessary soil parameters for the underground dam. The underground dam is an underground engineering structure where water is stored in the aquifer located on the impermeable formation by creating an impermeable curtain against the groundwater flow. Water can be obtained from underground dams by gravity or pumping. If the geological and topographic conditions are suitable, it is possible to construct underground dams in a way that they can be used by gravity. The Pozantı-Yukarıbelemedik underground dam project is located on the Karaçay stream approximately 3,160 m southeast of the Yukarıbelemedik Neighborhood of the Pozantı District of Adana. Within the scope of the thesis, engineering geology studies were carried out, underground dam axis location was determined, necessary engineering parameters were determined with research drillings and on-site tests. 5 basic drilling wells were opened at the determined axis location, underground geology was determined. There is alluvium with a thickness of 14 meters at the axis location, and andesite is the main rock at the bottom. The same units are observed in the storage area. Permeability and pressurized water tests were carried out to determine the permeability of the units in the drilling wells opened at the axis location, and according to the results of the pressurized water test and permeability test; it was determined that the units at the pond axis location are permeable. As a result of the studies carried out, it was evaluated that impermeability can be provided with cement injection in the permeable sections of the axis location, water can be retained in the storage area by extending the infiltration length due to the decrease in the permeability value towards the depth, and that it will not create a negative effect in terms of storage.