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...

Soil compaction can affect crop growth and greenhouse gas emission and information is required of how both these aspects are affected by compaction intensity and weather. In this paper we describe treatments of compaction intensity and their effects on soil physical conditions and crop growth in loam to sandy loam cambisol soils. Soil conditions and crop performance were measured over three sea...

Compaction characteristic of the surface layer asphalt mixture (13-type gradation mixture) was studied using Superpave gyratory compactor (SGC) simulative compaction tests. Based on analysis of densification curve of gyratory compaction, influence rules of the contents of mineral aggregates of all sizes and asphalt on compaction characteristic of asphalt mixtures were obtained. SGC Tests show t...

The cold compaction of an aggregate of powder is treated from the viewpoint of crystal plasticity theory. The contacts between particles are treated as compaction planes which yield under both normal and shear straining. The hardening of each plane represents both geometric and material hardening at the contacts between particles; the macroscopic tangent stiffness can be written in terms of the...

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...

Overtopping, internal erosion, and piping are the main causes of accidents and failures of embankments for dams, lagoons, and levees. A key parameter in the failure of these structures is the erodibility of the soil materials used in construction of the embankments. The soil materials are typically constructed based on compaction specifications. The jet erosion test (JET) has been developed to ...

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...

The recession flow analysis of Brutsaert and Nieber [1977] extended by Troch et al. [1993] to estimate aquifer parameters (saturated hydraulic conductivity and mean aquifer depth) is examined by means of a numerical model. It is found to be reliable for the estimation of the catchment-scale saturated hydraulic conductivity and mean aquifer depth. Increasing the complexity of the synthetic water...