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Intensive use of land resources in arid and semi-arid regions exert serious pressures on groundwater resources and jeopardize further socio-economical developments. The Amman-Zarqa Basin (AZB), the most vital basin in Jordan, is facing recent groundwater deterioration due to a very large increase in water demands for domestic, agricultural, and industrial uses. The objectives of this paper were to quantify the degree of contamination in the basin by evaluating the characteristics, distribution and seasonal variations of two pollution indicators (nitrate concentration and salinity) and to determine the impacts of human activities (land use) on groundwater quality. Based upon long-term data of groundwater samples collected from 538 wells across the AZB, spatial analyses indicated that both indicators have a strong spatial dependence and are anisotropically distributed. Prediction maps of Ordinary Kriging and Indicator Kriging provided detailed indications of the major and minor sources of pollution in the basin. Inefficient wastewater treatment plants, industrial activities and agricultural practices were responsible for 91, 85, and 25% salinization of nearby wells, respectively. Nitrate pollution had reached 73% above threshold (50 mg/L) in some cases. The temporal analyses estimated the salinity buildup rate to be around 8 9 10 -2 lS/cm per day, while nitrate buildup rate was estimated to be around 6 9 10 -2 mg/L per day. Remote sensing and spatial analyses helped greatly in groundwater quality assessment not only in providing the environmental status of the AZB but also in delineating the potential of contamination risk zones and their correlation to human activities. Furthermore, the paper suggests some environmental protection strategies that should be adopted to protect the vital groundwater resources of the basin from further deterioration.

Stable isotopes of water are known to provide information on mean altitudes of spring recharge areas, which is an important parameter for groundwater resources management especially in karstic environments. Very often, a lack of precipitation input data limits the possibility for an appropriate estimation of mean catchment altitudes. In the Jeita spring catchment, Lebanon, a characterization of precipitation input was possible with samples collected at six stations at varying altitudes (88 amount‐weighted monthly samples). A local meteoric water line for the Jeita spring catchment was characterized as δ2H = 6.04 * δ18O + 8.45 (R2 = .92) for a 2‐year observation period between October 2012 and September 2014. Integral samples from the snow layer were collected at 22 sites at altitudes ranging from 1,000 to 2,300 m above sea level at the end of February 2012 and February 2013, when snow height reached a maximum of more than 6 m at the highest peak in the catchment. Water samples were continuously collected from six springs (Jeita, Kashkoush, Labbane, Assal, Afqa, and Rouaiss). Jeita spring water samples were collected additionally in daily time steps during the snowmelt season in 2012. Mean isotope values of the sampled springs range from −6.8‰ to −8.2‰, and from −33‰ to −44‰, for δ18O and δ2H, respectively. The stable isotope data show that input variability (space and time, snow cover, and rainfall) has direct impacts on mean altitude estimates of spring catchments. A more profound interpretation of spring response to rainfall for six local springs in the Lebanon Mountains was possible in comparison to four earlier described springs collected in the Anti‐Lebanon Mountains in Syria.

The use of reclaimed water and its impact on groundwater quality in the middle and southern parts of the Jordan Valley are investigated. The chemical analyses indicate that nitrate and bacteriological pollution is widespread, and thus, seriously affects groundwater use. During the study, 365 water samples were collected from wells and springs to determine the water chemistry and the extent of nitrate pollution. Three hydrochemical facies are identifed, i. e., (Ca -(Mg) -Na -HCO 3 ), (Ca -Na -SO 4 -Cl) and (Ca -Na -Cl). The change of facies is accompanied by a gradual increase in the groundwater total dissolved solids (TDS), which is mainly controlled by evaporates and carbonates dissolution in the aquifer matrix. Water analyses indicate that the shallow aquifer in the study area is affected by non-point pollution sources, primarily from natural (manure) and chemical nitrogen (N)-fertilizers and treated wastewater used for agriculture. The concentration of nitrate in the groundwater ranges from 10 to 355 mg/L. Considerable seasonal fluctuations in groundwater quality are observed as a consequence of agricultural practices and other factors such as annual rainfall distribution and the Zarqa River flow. The noticeable levels of total coliform and Escherichia coli in the northern part of the study area may be attributed to contamination from the urban areas, intensive livestock production, and illegal dumping of sewage. Heavy metal concentrations in all samples were found to be significantly lower than the permissible limits for drinking water standards.

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