We present an analysis of migration effects on seismic reflection images of very shallow targets. Reflection objectives in engineering, groundwater, and environmental investigations commonly occur at depths between 2 and 50 m. Because the observation surface is near these imaged reflectors, optical distortion may be so small that migration will not have any effect on the seismic image and may t...

Groundwater nitrogen (N) and phosphorus (P) transport from ditch-drained, cultivated fields has not been adequately investigated in the Chesapeake Bay watershed.We monitored hydrology and groundwater Nand P concentrations in 26 shallow (~3 m [10 ft]) wells for 27 months on a heavily ditched, poultry-grain farm on Maryland's Lower Eastern Shore. Water tables fluctuated above and below shallow di...

A pulse of ‘T-labeled dissolved free amino acids (DFAA) was immobilized rapidly from groundwater discharged through cores of hyporheic sediment from an upland stream. Mean turnover distance within the cores was cl.5 cm but, once immobilized, DFAA carbon was retained for longer than would be expected if bacterial cycling was the only retention mechanism. It took 28 weeks for 88% of the original ...

Arsenic contamination of shallow groundwater is among the biggest health threats in the developing world. Targeting uncontaminated deep aquifers is a popular mitigation option although its long-term impact remains unknown. Here we present the alarming results of a large-scale groundwater survey covering the entire Red River Delta and a unique probability model based on three-dimensional Quatern...

Oxygen transfer in the capillary fringe (CF) is of primary importance for a wide variety of biogeochemical processes occurring in shallow groundwater systems. In case of a fluctuating groundwater table two distinct mechanisms of oxygen transfer within the capillary zone can be identified: vertical predominantly diffusive mass flux of oxygen, and mass transfer between entrapped gas and groundwat...

The potential of using tree core samples to detect and monitor natural attenuation of perchloroethene (PCE) in groundwater was investigated at a PCE-contaminated site. In the area of the known plume with PCE concentrations between 0.004 and > 40 mg/L, cores were collected from tree trunks at a height of about 1 m above ground surface. Tree sampling of the site was completed in under six hours. ...

Future climate changes and the resulting modifications in anthropogenic activities will alter the interactions between rivers and groundwater. The quantification of these hydraulic interactions is absolutely necessary for achieving sustainable water use and requires accurate analytical methodologies. This report proposes an interdisciplinary approach to the quantitative and qualitative characte...

The present study aims to estimate the residence-time of groundwater based on bomb-produced Cl. Water samples were collected from some selected wells located around Al-Zulfi province, Riyadh central region, Saudi Arabia. Cl/Cl ratios in the water samples are determined by Inductively Coupled Plasma Mass Spectrometry (ICPMS) and Liquid Scintillation Counting (LSC). Cl/Cl ratios in the groundwate...

Background of the Arsenic Crisis The groundwater pollution caused by arsenic (please see Box 1) in a number of Asian countries has led to a major environmental crisis. Some recent estimates indicate that more than 35 million people in West Bengal (India), Nepal and Bangladesh are potentially at risk from drinking arsenic-contaminated water (Smith et al., 2000). The crisis has its roots in anoth...

The present study assessed the export of inorganic carbon, nitrogen, and phosphorus within a large agricultural basin in arid northwestern China. Groundwater of various depths and river water along a 160 km reach were sampled during contrasting flow conditions. Dissolved inorganic carbon (DIC) concentrations and δ13C-DIC values indicate that lithogenic carbonate weathering was the main source o...