Radionuclide Transport above a Near‐Surface Water Table: I. An Automated Lysimeter Facility for Near‐Surface Contaminant Transport Studies

1994 ◽  
Vol 23 (6) ◽  
pp. 1318-1329 ◽  
Author(s):  
S. Burne ◽  
H. S. Wheater ◽  
A. P. Butler ◽  
P. M. Johnston ◽  
P. Wadey ◽  
...  
Keyword(s):  
Surface Water ◽  
Contaminant Transport ◽  
Water Table ◽  
Radionuclide Transport ◽  
Near Surface ◽  
Transport Studies

Water table decline, springline desiccation and the early development of irrigated agriculture in the Wādi al-Ajāl, Libyan Fazzān

2004 ◽  
Vol 35 ◽  
pp. 95-112 ◽  
Author(s):  
Nick Drake ◽  
Andrew Wilson ◽  
Ruth Peiling ◽  
Kevin White ◽  
David Mattingly ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Table ◽  
Fourth Century ◽  
Farming System ◽  
Irrigated Agriculture ◽  
Near Surface ◽  
Plant Remains ◽  
Drying Up ◽  
First Millennium

AbstractUranium/Thorium (U/Th) and 226Ra dating has been applied to spring deposits in order to determine the timing of the drying up of springs in the Wādī al-Ajāl, Fazzān, Libya. These dates are compared with results of archaeological surveys of irrigation structures and archaeobotanical studies of plant remains to further our understanding of the factors that controlled the introduction of irrigated agriculture, its nature and timing.Though there are still important gaps in our understanding, the results suggest that by 3,100 ±125 BP surface water was either very scarce or nonexistent at the base of the escarpment, although the water table was probably very near the surface at the base of the Wādī in the vicinity of Jarma. Archaeobotanical evidence indicates that irrigated agriculture was introduced in the early part of the first millennium BC, soon after the desiccation of the springs and presumably in response to the fall in the water table and the increasingly scarce availability of surface water. No irrigation structures have been found that relate to this period, but the most likely scenario involves wells tapping the near surface water in the vicinity of Jarma. The earliest irrigation systems are foggaras which archaeological evidence suggests were probably introduced by the final few centuries BC, and definitely before the fourth century AD. The extensification of agriculture associated with extensive foggara development broadly corresponds with archaeobotanical evidence for an intensification and diversification of agriculture involving the introduction of a farming system utilising both winter and summer crops. There are likely to be strong connections between these two developments and that of the rise of the Garamantes.

scholarly journals An evaluation of water quality at Sandhill Wetland: implications for reclaiming wetlands above soft tailings deposits in northern Alberta, Canada

2021 ◽  
Author(s):  
Jeremy A. Hartsock ◽  
Jessica Piercey ◽  
Melissa K. House ◽  
Dale H. Vitt
Keyword(s):  
Water Quality ◽  
Electrical Conductivity ◽  
Surface Water ◽  
Water Chemistry ◽  
Water Quality Monitoring ◽  
Total Alkalinity ◽  
Near Surface ◽  
Water Quality Guidelines ◽  
Quality Guidelines ◽  
Annual Water

AbstractThe experimental Sandhill Wetland is the first permanent reclamation of a composite tailings deposit, and annual water quality monitoring is of specific interest for evaluating and predicting long-term reclamation performance. Here, we present water chemistry monitoring data obtained from Sandhill Wetland (years 2009–2019) and compare results to twelve natural reference wetlands and to environmental quality guidelines for Alberta surface waters. By comparing water quality at Sandhill Wetland and natural sites to established guidelines, we can begin to document the natural background water quality of wetlands in the region and examine if guideline exceedances are seen in natural undisturbed environments, or appear only at active reclamation sites. At Sandhill Wetland the dominant ions in near-surface water were bicarbonate, sulfate, chloride, sodium, calcium, and magnesium. Since the first growing season concentrations for these ions have increased annually, causing concurrent increases in electrical conductivity. In year 2019, water chemistry at Sandhill Wetland was most comparable to regional saline fens, systems that exhibit elevated electrical conductivity and high sodicity. Near-surface water at Sandhill Wetland exceeded water quality guidelines for three substances/properties (dissolved chloride, iron, and total alkalinity) in the most recent year of monitoring. The saline fen natural sites also exceeded water quality guidelines for the same chemical substances/properties, suggesting guideline exceedances are a norm for some natural wetland site types in the region. Of note, in each year of monitoring at Sandhill Wetland, dissolved organic compounds evaluated in sub- and near-surface water were below detection limits.

scholarly journals Replenishment of near‐surface water ice by impacts into Ceres’ volatile‐rich crust: Observations by Dawn’s Gamma Ray and Neutron Detector

2021 ◽  
Author(s):  
T. H. Prettyman ◽  
N. Yamashita ◽  
M. E. Landis ◽  
J. C. Castillo‐Rogez ◽  
N. Schörghofer ◽  
...  
Keyword(s):  
Surface Water ◽  
Neutron Detector ◽  
Gamma Ray ◽  
Near Surface ◽  
Water Ice
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