Karst aquifers occur in a range of climatic and geologic settings. Nonetheless, they are commonly characterized by their vulnerability to water-quality impairment. Two karst aquifers, the Edwards aquifer in south-central Texas and the Upper Floridan aquifer in western Florida, were investigated to assess factors that control the movement of contaminants to public-supply wells (PSWs). The geoche...

Mashhad Plain affects by a series of active faults in the northern margin of the Binalud and the southern margin of the Kopet-Dagh mountain ranges. The activity of these faults forms the morphology of the stepped bedrock of the Plain. In addition, the faults’ activities in the Quaternary period are the main effective parameters in thickness and texture of aquifer deposits in Mashhad Plain. In t...

In the eastern Grand Canyon, secondary porosity created by north trending faults, folds, and breccia pipes, facilitates groundwater flow through the South Rim carbonate aquifer. Springs associated with the South Rim Aquifer have low H concentrations, [Ca']/[Mg '] ratios close to unity, and variable uranium concentrations. For a geochemical comparison, springs are subcategorized on the basis of ...

Denitrification, the microbial reduction of nitrate (NO3) in groundwater, has three requirements: limited oxygen, bacteria capable of mediating the reaction, and electron donors for the bacteria to use in the redox reactions. The critical factor for aquifer denitrification is the concentrations of electron donors. Without an adequate supply of electron donors, bacteria cannot reduce concentrati...

[1] We present a robust optimization method for estimating aquifer storage parameters (specific yield or storativity) using the Gravity Recovery and Climate Experiment (GRACE) data, in situ well level observations, and other ancillary information. Uncertainty inherent in the remotely sensed and in situ time series can adversely affect the parameter estimation process and, in the worse case, mak...

This paper explores the signi®cance of groundwater dominance in the surface water system through a combination of review and an exposition of the general hydrology, ecology and geomorphology of rivers draining the main UK aquifers. Groundwater dominance is shown to vary according to the nature of the aquifer lithology, the mechanism of groundwater:surface water interaction and the scale at whic...

Localized studies of arsenic (As) in Bangladesh have reached disparate conclusions regarding the impact of irrigation-induced recharge on As concentrations in shallow (≤50 m below ground level) groundwater. We construct generalized regression models (GRMs) to describe observed spatial variations in As concentrations in shallow groundwater both (i) nationally, and (ii) regionally within Holocene...

drastic is known as the most prototype models of groundwater vulnerability assessment. the drastic constitutes from seven schematic parameters consisting: depth to groundwater, recharge to aquifer, aquifer geology, and surface soil texture, impact of vadoze zone and hydraulic conductivity. in this study the models parameters were extracted by the main schematic maps of model. instead using the ...

Most Middle Eastern and North African regions are characterized by an arid semi-arid climate. As such, the drinking water supply management have become a challenging task for local regional authorities. The Mio-Plio Quaternary aquifer of Barika area is only irrigation reservoir in region. objective this paper to identify origin evolution process groundwater mineralization using major elements a...

Saltwater intrusion is an ideal target for mapping with airborne electromagnetic techniques because of the high electrical conductivity of saline water and its contrast with that of freshwater. Using electromagnetic sensors to measure the electromagnetic response of the ground at several frequencies, information from various depths is obtained. The electromagnetic response is then converted to ...