Stable isotopes (deuterium and oxygen‐18) of precipitation and four springs of the Figeh spring system were studied between March 2011 and July 2012 in the karstic Anti‐Lebanon Mountains in Western Syria. Almost two thirds of the drinking‐water supply of Damascus City, the capital of Syria, is being exploited from the Figeh spring system. About 70 samples were collected from precipitation, and 1000 samples from springs in at least weekly time resolution. Observed mean values for Figeh spring system agree well with published data from earlier studies and are between −8.7‰ and −7.3‰ for δ18O and −50‰ and −40‰ for δ2H. Time series indicate seasonal patterns and short‐term influences, reflecting direct contribution from fast runoff components during snowmelt. Deuterium excess values between 23‰ and 14‰ for the spring samples correspond to precipitation originating from the Mediterranean Sea. Own precipitation collected over one season at two stations leads to altitude effects of −0.14‰/100 m and −1.15‰/100 m for δ18O and δ2H, respectively, which are lower than those reported in earlier work. Mean catchment altitudes were estimated using values for low‐flow periods, which lead to 1800 m a.s.l. for Figeh Main spring, 1500 m a.s.l. for Haroush spring and about 1100 m a.s.l. for the springs Kefar Aloumed and Ein Habeeb. Stable isotope concentrations uniquely characterize springs that are located close together, and estimated recharge catchment altitudes allow a profound risk management. Catchment altitude estimations strongly depend on a proper description of precipitation stable isotope input. Copyright © 2016 John Wiley & Sons, Ltd.

The Tanour spring is one of the several karst springs located in the northern part of Jordan. Water samples from the Tanour spring and precipitation were collected in the area of Ajloun in NW Jordan for the analysis of stable oxygen and hydrogen isotopes to evaluate the spring response to precipitation events. Rainwater and snow samples were collected from different elevations during winters of 2013-2014 and 2014-2015. In addition, spring samples were collected between December 2014 and March 2015. δ(18)O values in rainwater vary from -3.26 to -17.34 ‰ (average: -7.84 ± 3.23 ‰), while δ(2)H values range between -4.4 and -110.4 ‰ (average: -35.7 ± 25.0 ‰). Deuterium excess ranges from 17.8 to 34.1 ‰ (average: 27.1 ± 4.0 ‰). The Local Meteoric Water Line for the study area was calculated to be δ(2)H = 7.66*δ(18)O + 24.43 (R(2) = 0.98). Pre-event spring discharge showed variation in δ(18)O (range -6.29 to -7.17 ‰; average -6.58 ± 0.19 ‰) and δ(2)H values (range -28.8 to -32.7 ‰; average: -30.5 ± 1.0 ‰). In contrast, δ(18)O and δ(2)H rapidly changed to more negative values during rainfall and snowmelt events and persisted for several days before returning to background values. Spring water temperature, spring discharge, and turbidity followed the trend in isotopic composition during and after the precipitation events. The rapid change in the isotopic composition, spring discharge, water temperature, and turbidity in response to recharge events is related to fast water travel times and low storage capacity in the conduit system of the karst aquifer. Based on the changes in the isotopic composition of spring water after the precipitation events, the water travel time in the aquifer is in the order of 5-11 days.

In this work, a 3D groundwater flow model integrating all important geological features of the hydrogeological system is developed to investigate hydrological processes in the Wadi Kafrein area of Jordan. A large amount of available geological and hydrological data is integrated to construct a 3D groundwater flow model for the Wadi Kafrein area. Using the newly developed mapping approach, the translation of the highly detailed geological formations to an unstructured finite element grids, can be accomplished with high precision. The existing data set for model calibration is scarce, which is a typical situation for many hydrogeological case studies. At first, the steady state calibration of the groundwater model is carried out based on the observation wells. Then, the time and space-dependent recharge from precipitation are applied at the top surface of the finite element model. The transient simulation is conducted during the period of 1996-2008 considering the abstraction rates of the production wells and discharge of the springs. The calculated water levels are close to the observed values. The difference is partly caused by return flows from irrigation and the groundwater inflow from the adjacent aquifers which are not taken into consideration so far. Since the Wadi Kafrein area is an important agricultural area in the semiarid region of the Lower Jordan Valley, the model developed in this study can be regarded as a useful tool for analyzing the hydrological processes and improving groundwater management practices elsewhere affected by similar geological and hydrogeological conditions.

No abstract

No abstract