Vulnerability assessment to delineate areas that are more susceptible to contamination from anthropogenic sources has become an important element for sensible resource management and land use planning. This contribution aims at estimating aquifer vulnerability by applying the DRASTIC model as well as utilizing sensitivity analyses to evaluate the relative importance of the model parameters for ...

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...

The Nubian Sandstone complex in the western desert is a part of the major regional Nubian aquifer system comprising West Africa. The different rock strata deposited in localities forming the units of the aquifer system. Farafra Oasis lies in the northern part of the Dakhla basin. In its southern region, the Nubian Sandstone (deep aquifer) is overlained by Dakhla shale but in the central and nor...

Aquitards are capable of generating and preserving large amounts of chemicals. The release of the chemicals from the aquitards poses a potential contamination risk to groundwater that may be used as a drinking water source. This work aimed to identify the contribution of hydrogeochemical processes in the aquitards to groundwater hydrochemistry in the underlying confined basal aquifer by studyin...

Mean groundwater levels of a multi-layered coastal leaky aquifer system are considered. The system consists of an unconfined aquifer, a confined aquifer and a semi-permeable layer between them. Both exact asymptotic solutions and approximate perturbation solutions are derived for multi-sinusoidal-component sea tide. At inland places far from the coastline, the perturbation solutions show a good...

This study presents an approach for obtaining limited sets of realizations of hydraulic conductivity (K) of multiple aquifers using simulated annealing (SA) simulation and spatial correlations among aquifers to simulate realizations of hydraulic heads and quantify their uncertainty in the Pingtung Plain, Taiwan. The proposed approach used the SA algorithm to generate large sets of natural logar...

Tidal fluctuations in a leaky confined coastal aquifer are damped significantly due to leakage into an overlying phreatic aquifer. Jiao and Tang [1999] presented an analytical solution to a simple model describing this phenomenon. Their solution assumes that the tidal fluctuations in the overlying phreatic aquifer are negligible (i.e., a static phreatic aquifer). Here we examine dynamic effects...

A USGS investigation into the transport of contaminants to public-supply wells (PSWs) in four distinctly different aquifers demonstrates how differences in the chemistry of water produced by PSWs and nearby monitoring wells can reveal where and how contamination-susceptible water enters PSWs. This knowledge can be translated into improved monitoring strategies and protection plans. Samples were...

Intermontane basins in the Trans-Pecos region of westernmost Texas and northern Chihuahua, Mexico, are target areas for disposal of interstate municipal sludge and have been identified as possible disposal sites for low-level radioactive waste. Understanding ground water movement within and between these basins is needed to assess potential contaminant fate and movement. Four associated basin a...

Analytical studies are carried out to investigate groundwater head changes in a coastal aquifer system in response to tidal fluctuations. The system consists of an unconfined aquifer, a semi-confined aquifer and a semi-permeable confining unit between them. An exact analytical solution is derived to investigate the influences of both leakage and storage of the semi-permeable layer on the tide-i...