Havşari-Zerban (Çelikhan-Adıyaman) Karst Sisteminin Hidrojeolojik İncelenmesi

Abstract

The objective of this thesis study is to investigate the hydrogeological conceptual model of the Havşari-Zerban Karst System (HZKS), which is located in the Çelikhan district of Adıyaman province and is utilized for drinking, domestic, and irrigation purposes, with a focus on its recharge-circulation-storage-discharge mechanisms. The Zerban and Havşari springs discharge through aquifers that composed of Paleozoic-Mesozoic-aged Çayderesi Formation marbles, with average flow rates of 0.615 m3/s and 0.847 m3/s, respectively. The surface drainage area, covering 58.6 km2, was selected as the study area for the springs, but due to the karst system's nature, a broader region (300 km2) was examined, taking into account the limestone outcrop. The study area and its surroundings were evaluated concerning geological, tectonic, morphological, climatic, hydrological, and hydrogeological characteristics. This evaluation was conducted based on three fieldwork periods and existing data, leading to the development of a conceptual hydrogeological model for the Havşari-Zerban Karst System (HZKS). According to the results of hydrogeochemical analyses, all water points in the area discharge CaHCO3 type waters. Based on the water budget calculations using precipitation, temperature, and flow data, it has been determined that the Zerban and Havşari springs require additional precipitation or contributions from outside the surface drainage area to sustain their discharges. Therefore, it is believed that the Havşari and Zerban springs are discharging from separate systems. Particularly, the Havşari Spring, which discharges predominantly through the Sürgü Fault, is thought to have its recharge along this fault. The recharge on the HZKS occur from Mediterranean-derived precipitation. Based on tritium analyses, it has been determined that groundwater in the study area consists mostly of young waters, indicating that they are primarily originate by precipitation occurring after 1950. It has been determined that recharge in the HZKS occurs extensively from precipitation. As autogenic-diffuse. When examining the hydrographs of the Zerban and Havşari springs with flow data available from 1984 to 2021 for each recession period, the high coefficient of variation observed in spring discharges, the shape of the flow hydrographs, and the changes in recession coefficients all indicate that the storage and circulation occur within the HZKS predominantly along well-developed karstic fracture systems and partially through karstic channels.