نتایج جستجو برای: shallow groundwater
تعداد نتایج: 62766 فیلتر نتایج به سال:
Arsenic in groundwater has been a concern in South and Southeast Asia for more than a decade. We explore here the possibility that hydrogeologic factors recently shown to influence the distribution of arsenic might also affect the level of contamination of shallow (<20 m) wells with microbial pathogens. A total of 96 shallow tube wells in two nearby villages of Bangladesh were surveyed during t...
The chemical and isotopic (Sr/Sr, B, Ssulfate, Owater, Nnitrate) compositions of water from the Lower Jordan River and its major tributaries between the Sea of Galilee and the Dead Sea were determined in order to reveal the origin of the salinity of the Jordan River. We identified three separate hydrological zones along the flow of the river: (1) A northern section (20 km downstream of its sour...
Rain, fog drip, shallow soil water and groundwater were collected for two years (2002-2003) for stable isotopic analysis, at a tropical seasonal rain forest site in Xshuangbanna, Southwest China. The fog drip water ranged from -30 to +27 per thousand in deltaD and -6.2 to +1.9 per thousand in delta(18)O, conforms to the equation deltaD=7.64delta(18)O+14.32, and was thought to contain water that...
In the irrigated western U.S. disposal of drainage water has become a significant economic and environmental liability. Development of irrigation water management practices that reduce drainage water volumes is essential. One strategy combines restricted drainage outflow (by plugging the drains) with deficit irrigation to maximize shallow groundwater consumption by crops, thus reducing drainage...
Proglacial groundwater-fed features, such as seeps, substantially impact proglacial geomorphology, hydrology, and ecology. However, there is a paucity of research on the impacts of climate change and glacial retreat on the extent of these important features. This paper aims to investigate the impact of glacial retreat on proglacial groundwater levels and on the extent of groundwater-fed seeps. ...
A tracer test to examine in situ denitrification in shallow groundwater by a piezometer with a packer system used bromide as a tracer of dilution and acetylene (10%) to block the denitrification process at the nitrous oxide stage. During the test, dissolved oxygen, nitrate (NO3 -), bromide (Br-), nitrous oxide (N2O) and dissolved organic carbon (DOC) were measured. To calibrate the experimental...
California's dairies are the largest confined animal industry in the state. A major portion of these dairies, which have an average herd size of nearly 1000 animal units, are located in low-relief valleys and basins. Large amounts of liquid manure are generated and stored in these dairies. In the semi-arid climate, liquid manure is frequently applied via flood or furrow irrigation to forage cro...
Water and gas samples were collected from (1) nine shallow groundwater aquifers overlying Marcellus Shale in north-central West Virginia before active shale gas drilling, (2) wells producing gas from Upper Devonian sands and Middle Devonian Marcellus Shale in southwestern Pennsylvania, (3) coal-mine water discharges in southwestern Pennsylvania, and (4) streams in southwestern Pennsylvania and ...
Little is known about the importance of drainage/irrigation channels and biogeochemical processes in arsenic distribution of shallow groundwaters from the Hetao basin. This investigation shows that although As concentrations are primarily dependent on reducing conditions, evaporation increases As concentration in the centre of palaeo-lake sedimentation. Near drainage channels, groundwater As co...
Despite decades of measurements, the nitrogen balance of temperate forest catchments remains poorly understood. Atmospheric nitrogen deposition often greatly exceeds streamwater nitrogen losses; the fate of the remaining nitrogen is highly uncertain. Gaseous losses of nitrogen to denitrification are especially poorly documented and are often ignored. Here, we provide isotopic evidence (δ(15)NNO...
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