Hydrochemistry and environmental isotopes of spring water and their relation to structure and lithology identified with remote sensing methods in Wadi Araba, Egypt

Abstract

Springs located at the historical sites of Wadi Araba (Eastern Desert of Egypt) and emerging from the escarpments of the Northern and Southern Galala Plateaus were investigated. A combination of methods, including hydrochemistry, stable and radioisotope composition, and structural analyses based on satellite data, provided information about the structure of the subsurface and the derived groundwater flow paths. Satellite images reveal karst features within the northern plateau, e.g. conical landforms. Karstic caves were documented along both escarpments. Chemical analysis of floodwater from Wadi Araba indicates higher concentrations of terrestrial salts compared to floodwaters from central and southern parts of the desert. δ18O and δ2H signatures in spring waters resemble those of floodwater and fall on the global meteoric water line, confirming their fast infiltration with minor influence of evaporation. The aquifer feeding the springs of the Northern Galala Plateau has low retention and the springs dry out quickly, even after heavy rainfall. Contrastingly, 3H activities in springs emerging from the Southern Galala Plateau refer to much slower subsurface passage. With respect to 3H content (3.8 TU) in recent flood waters, the spring water at Southern Galala Plateau contains about 40% recently recharged groundwater. However, its largest spring—the St. Antony spring—discharges water with a radiocarbon age of about 15,000 years. In combination with this spring’s constant and high discharge over a period of several months, that age estimate suggests a large reservoir with moderate to high retention.

Saint Anthony Cave: Morphology, genesis, and age of one of the oldest religious shrines, Southern Galala Plateau, Eastern Desert, Egypt

“…Fahim Wannous et al, 2021), although the data of the latter study show a few springs with water temperatures 4 °C to 5 °C higher than the average annual air temperature in the area (23.36° C). Those latter few springs are considered slightly thermal or warm according to the 4 °C threshold of Schoeller (1962).…”

“…Total dissolved solids range from 1.344 g L −1 to 2.822 g L −1 , temperature ranges from 13 °C to 28.3 °C, and pH ranges from 6.9 to 8.5. The water type is mostly Cl (407−1,098 mg L −1 ), SO 4 (200−848 mg L −1 ), HCO 3 (129−405 mg L −1 ), and isotopic measurements suggest meteoric recharge (Wannous et al, 2021;Khalil et al, 2021).…”

“…The water chemistries of the springs of Saint Anthony and Maryam (Aladra) in February 2018 were brackish (1465 and 1547 mg L −1 dissolved salts, respectively) with a pH of 7.3 and 7.8, respectively. Their water types were Cl (407 and 437 mg L −1 , respectively)-SO 4 (314 and 349 mg L −1 , respectively)-HCO 3 (279 and 255 mg L −1 , respectively), and their temperatures were 24 °C and 17 °C, respectively (Wannous et al, 2021). In January 2016, the water chemistry of the Saint Anthony spring was brackish (1335 mg L −1 dissolved salts) with a pH 7.3 and a water type of Cl (450 mg L −1 ), HCO 3 (305 mg L −1 ), SO 4 (180 mg L −1 ) (Saint Anthony Monastery, unpublished data, 2016).…”

Applicability of Literature Values for Green–Ampt Parameters to Account for Infiltration in Hydrodynamic Rainfall–Runoff Simulations in Ungauged Basins

“…2). The details of the experimental setup are presented in Tatard et al [75], and and 2016) [77]. As a very exceptional occasion, manual discontinuous velocity measurements and corresponding discharge estimations could have been carried out during the flash flood event in March 2014, and are published in Hadidi [78].…”

Geochemical and Isotopic Constraints on the Recharge and Salinization Origin of Groundwater Aquifers in El Rina–Nihayaat, South Sinai, Egypt

“…This research investigates the chemical composition of groundwater and the use of isotopic tracers to unravel the hydrological cycle and understand water-rock interactions. Understanding the composition helps assess water quality, identify sources of contamination, and study natural processes influencing water chemistry [17]. Isotopic analysis involves studying the abundance of stable (e.g., oxygen-18, deuterium) in water molecules.…”