Abstract The Kathmandu Valley in Nepal is facing a water quantity and quality crisis due to rapid urbanization haphazard wastewater planning management. Annually, groundwater extractions the exceed capture, resulting table declines. Streams are often important sources of recharge (or destination discharges from) aquifers. However, stream-aquifer interactions poorly understood. To improve this u...

A polyphasic approach based on cultivation and direct recovery of 16S rRNA gene sequences was utilized for microbial characterization of an aquifer contaminated with chlorinated ethenes. This work was conducted in order to support the evaluation of natural attenuation of chlorinated ethenes in groundwater at Area 6 at Dover Air Force Base (Dover, DE). Results from these studies demonstrated the...

Transport behaviors of unidentified flagellated protozoa (flagellates) and flagellate-sized carboxylated microspheres in sandy, organically contaminated aquifer sediments were investigated in a small-scale (1 to 4-m travel distance) natural-gradient tracer test on Cape Cod and in flow-through columns packed with sieved (0.5-to 1.0-mm grain size) aquifer sediments. The minute (average in situ ce...

Gisser and Sánchez (1980a) state the conditions under which welfare gains from policy intervention are negligible in aquifer management, when compared with non-regulation or “free market” outcomes. This is the so-called Gisser-Sánchez effect (GSE), which has been supported by the ensuing literature during recent decades. The GSE requires a number of assumptions, among which is the disregard for...

Head measurements at a single observation well during a cross-hole pumping test carry a great amount of information about aquifer heterogeneity other than the average property of the aquifer as implied in Theis analysis of aquifer test. In this commentary, we use simple examples and a probabilistic reasoning approach based on Darcy’s law to unravel this information, buried in the results of qua...

Introduction Guarani Aquifer System (SAG) is the formal denomination for a transboundary aquifer underlying four countries (Argentina, Brazil, Paraguay and Uruguay) in South America. Due to its strategic importance, a joint research project aiming for sustainable management and preservation of the aquifer was initiated by the four neighbour countries together. In this work, an overview of hydro...

Please cite this article in press as: Ayotte, J.D., trace elements at water-supply wells. Appl. Geo The effects of human-induced alteration of groundwater flow patterns on concentrations of naturallyoccurring trace elements were examined in five hydrologically distinct aquifer systems in the USA. Although naturally occurring, these trace elements can exceed concentrations that are considered ha...

Groundwater nitrate contamination of the aquifer in the Central Valley, California is a major problem due to intense agricultural practice over the last decades. Excessive loading of fertilizer and manure in combination with hydrogeological parameters and geochemical conditions have enhanced the downward percolation of nitrate into the aquifer. A spatial variance-based geographical detector met...

Artificial neural networks have proven to be an attractive mathematical tool to represent complex relationships in many branches of hydrology. Due to this attractive feature, neural networks are increasingly being applied in subsurface modeling where intricate physical processes and lack of detailed field data prevail. In this paper, a methodology using modular neural networks (MNN) is proposed...