Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Citation - Scopus: 1Estimating Groundwater Recharge Through Multiple Methods: Southern Sections of the Western Afar Rift Margin and Associated Rift Floor(Springer, 2025) Gidafie, Dereje; Baba, Alper; Nedaw, Dessie; Azagegn, Tilahun; Abebe, Bekele; Baba, Alper; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis study quantifies groundwater recharge in the southern sections of the western Afar Rift margin and associated rift floor by employing multiple methods, including Water balance, Chloride Mass Balance, WetSpass modeling, and Baseflow separation controlled by radon measurement. The mean annual groundwater recharge rates obtained from the first two methods are 114.39 mm/year, and 92.37 mm/year respectively. The spatially distributed recharge determined from the WetSpass model shows the rift margin has higher values than the rift floor, and results in a mean recharge of 100.88 mm/year. The baseflow separation method calculates 136.7 mm/year and 17.86 mm/year at the outlets of the marginal grabens and inside the rift floor respectively. The higher value suggests additional groundwater flows from the adjacent plateau to the rift margin, driven by the extended columnar basalt and transverse structures. In contrast, the presence of highly faulted Dalha basalt along the Arcuate Accommodation Zones (AAZ) promotes groundwater seepage, leading to lower values in the rift floor. However, from the previous hydrochemical and isotope analysis, groundwater flows from the rift margin to the rift floor, due to the presence of transverse structures create preferential pathways that connect these areas. Hence, the rift floor can have moderate recharge. Therefore, the WetSpass model and Base-flow separation methods, supported by other techniques, provide reliable results in tectonically active areas like the Afar Triangle and arid to semi-arid regions. Last but not least, the study underscores the importance of using multiple techniques for accurate assessments of recharge rates and mechanisms in similar areas.Article Citation - WoS: 2Citation - Scopus: 3Evaluation of the Source and Mechanisms of Groundwater Recharge for the Southern Sections of the Western Afar Rift Margin and Associated Rift Floor(Elsevier, 2024) Gidafie, Dereje; Baba, Alper; Nedaw, Dessie; Azagegn, Tilahun; Abebe, Bekele; Baba, Alper; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyStudy area: Southern Sections of Western Afar rift margin and associated rift floor. Study focus: The purpose of this study is to identify the source and mechanisms of groundwater recharge based on geological, hydrochemical, and environmental isotope studies. New hydrogeological insights: The investigation illustrate that the columnar jointed basalt was extended from the plateau to the rift margin. In addition, transverse structures trending NW-SE and NE-SW connect the plateau to the rift margin and the marginal grabens to the rift floor. The hydrochemical interpretations with EC and TDS shows that the groundwater from the plateau has evolved from Ca-dominated and slightly mineralized to Na-dominated and highly mineralized to the rift floor. Isotopically, the deep groundwater systems are depleted in the entire physiography in contrast to the shallow groundwater systems. Radon measurements are higher at the outlets of the marginal grabens and between the rift margin and the rift floor, suggesting groundwater feeds the river. A comprehensive analysis of the aforementioned results suggests that the deep circulating groundwater is recharged in the plateau and escarpment and chemically altered with increasing depth and along its preferential flow path into the rift floor. Therefore, the plateau area is the main source of recharge for the western Afar rift margin and associated rift floor, due to the presence of preferential pathways, mainly the columnar jointed basalts and crossstructures.