scholarly journals Aquifer and Pond Relationship Under Potential Influence of Eucalyptus and Sugarcane

2021 ◽  
Author(s):  
Rafael Terada ◽  
Ricardo Hirata ◽  
Paulo Galvão ◽  
Fernando Saraiva ◽  
Norio Tasse ◽  
...  
Keyword(s):  
Major Ions ◽  
Flow System ◽  
Pond Water ◽  
Shallow Aquifer ◽  
Potential Influence ◽  
Local Flow ◽  
Discharge Area ◽  
Geophysical Surveys ◽  
Before And After ◽  
Flow Directions

Abstract A hydraulic interaction between a pond and shallow aquifer in a watershed surrounded by cultivations of sugarcane and eucalyptus trees was evaluated in Brazil. The pond, located in lower topographic levels, was prematurely interpreted as the local shallow aquifer's discharge area, suggesting the groundwater could flow towards the pond. However, water table gradients indicated opposite directions, bringing up questions about the eucalyptus root's potential to access groundwater, consequently lowering the water level and changing the groundwater flow directions. Physicochemical parameters, stable isotopes of δ18O and δ2H, major ions analysis were determined in samples of groundwater and pond water; and geophysical surveys and groundwater level measurements were performed before and after the eucalyptus cutting. The results showed 1) the eucalyptus does not have a significant influence on the groundwater dynamic; 2) the pond behaves as a recharge, not a discharge area; and 3) previously considered as a local flow, the interaction between groundwater and pond is determined by an intermediate flow system, controlled by a near spring, independently of the seasonal variation and land uses.

scholarly journals The Effect of River Valleys and the Upper Cretaceous Aquitard on Regional Flow in the Dakota Aquifer in the Central Great Plains of Kansas and Southeastern Colorado

1995 ◽  
pp. 11-30
Author(s):  
P. Allen Macfarlane
Keyword(s):  
Hydraulic Conductivity ◽  
Great Plains ◽  
Upper Cretaceous ◽  
Flow System ◽  
Arkansas River ◽  
Local Flow ◽  
Discharge Area ◽  
Regional Flow ◽  
Regional Hydrogeology ◽  
Vertical Hydraulic Conductivity

In his reports on the regional hydrogeology of the central Great Plains, in particular southeastern Colorado and southwestern and central Kansas, Darton considered the Dakota aquifer to be a classic example of an artesian system. Computer simulations of the flow system in this study, however, suggest that the Dakota is not a regional artesian aquifer in the classic sense. Sensitivity analysis of a steady-state vertical profile flow model demonstrates that the flow system in the upper Dakota in western Kansas is heavily influenced by the Upper Cretaceous aquitard, the Arkansas River in southeastern Colorado, and rivers in central Kansas, such as the Saline, that have eroded through the aquitard and into the Dakota to the west of the main outcrop area of the aquifer. The model shows that local flow systems and the vertical hydraulic conductivity of the Upper Cretaceous aquitard heavily influence the water budget and the flow patterns. The aquitard restricts recharge from the overlying water table to underlying aquifers in western Kansas because of its considerable thickness and low vertical hydraulic conductivity. The Arkansas River intercepts ground-water flow moving toward western Kansas from recharge areas south of the river and further isolates the upper Dakota from sources of freshwater recharge. In central Kansas, the Saline River has reduced the distance between confined portions of the aquifer and its discharge area. In essence, this has improved the hydraulic connection between the confined aquifer and its discharge area, thus helping to generate subhydrostatic conditions in the upper Dakota upgradient of the river.

The evolution and non-fickian flow of local stagnant zones in hierarchically nested groundwater flow system under different rainfall infiltration intensity

2021 ◽  
Author(s):  
Ronglin Sun ◽  
Liqun Jiang ◽  
Xing Liang ◽  
Menggui Jin
Keyword(s):  
Climate Change ◽  
Groundwater Flow ◽  
Flow System ◽  
Rainfall Infiltration ◽  
Stagnant Zone ◽  
Local Flow ◽  
Discharge Area ◽  
Directional Flow ◽  
Regional Flow ◽  
Flow Systems

<p>Groundwater plays an active role in certain geologic processes that has been recognized in numerous subdisciplines for a long time. According to Toth (1963, 2009), gravity-driven regional groundwater flow is induced by elevation differences in the water table and its pattern is self-organized into hierarchical sets of local, intermediate and regional flow systems.  Convergence of two flow systems results in a stagnant zone called hydraulic trap which is under the discharge area, and diverge of two flow systems results in a stagnant zone called quasi-stagnant zone which is under the water divide. These stagnant zones have been found to be critical to accumulation of transported mineral matter. Based on analytical and numerical solutions, some researchers reported that the local stagnant point or zone that are located under the local counter directional flow system. There is a question that whether hydraulic trap and quasi-stagnant zone is separate or integrate, and whether they are located under the discharge area or water divide or counter directional flow systems.</p><p>In this study, two-dimensional numerical cross-sectional model is used to investigate the effect of climate change on local stagnant zones and whether the hydraulic trap and quasi-stagnant zone is separate or integrate. Considering the climate change of basin and the change of rainfall infiltration intensity, a flux upper boundary is used to simulate the rainfall recharge. Then a synthetic homogeneous sandbox with three potential sinks is used to validate the evolution of the hierarchical nested groundwater flow systems considering different rainfall infiltration intensity. Salt tracer test is used to investigate the effect of stagnant zones on solute transport.</p><p>According to numerical results, we concluded that the hydraulic traps and quasi-stagnant are possible to be separate only for simple local systems and the two local stagnant zones are located on two sides of the counter directional flow system. When nested flow systems occur, such as local-intermediate, local-intermediate-local, local-regional, the local hydraulic traps and quasi-stagnant zones are always integrated under the local counter directional flow systems. Laboratory results show that when the rainfall infiltration intensity reduce, the groundwater flow pattern will change and the penetration depth and scope of counter directional local flow system will decrease. The corresponding local stagnant zone will slowly be closing to the discharge area of that counter directional local flow system. Salt tracer tests show that there are obvious non-fickian phenomenon in the local stagnant zones in hierarchically nested flow systems even in the homogeneous aquifer.</p>

scholarly journals Modeling Groundwater Flow System of a Drainage Basin in the Basement Complex Environment of Southwestern Nigera

2018 ◽  
Vol 1 ◽  
pp. 1-7
Author(s):  
Akinola S. Akinwumiju ◽  
Martins O. Olorunfemi
Keyword(s):  
Groundwater Flow ◽  
Drainage Basin ◽  
Flow System ◽  
Subsurface Water ◽  
Complex Environment ◽  
Basement Complex ◽  
Local Flow ◽  
Groundwater Flow System ◽  
Regional Flow ◽  
Flow Directions

This study attempted to model the groundwater flow system of a drainage basin within the Basement Complex environment of Southwestern Nigeria. Four groundwater models were derived from Vertical Electrical Sounding (VES) Data, remotely sensed data, geological information (hydrolineaments and lithology) and borehole data. Subsequently, two sub-surface (local and regional) flow systems were delineated in the study area. While the local flow system is controlled by surface topography, the regional flow system is controlled by the networks of intermediate and deep seated faults/fractures. The local flow system is characterized by convergence, divergence, inflow and outflow in places, while the regional flow system is dominated by NNE-SSW and W-E flow directions. Minor flow directions include NNW-SSE and E-W with possible linkages to the main flow-paths. The NNE-SSW regional flow system is a double open ended flow system with possible linkage to the Niger Trough. The W-E regional flow system is a single open ended system that originates within the study area (with possible linkage to the NNE-SSW regional flow system) and extends to Ikogosi in the adjoining drainage basin. Thus, the groundwater drainage basin of the study area is much larger and extensive than its surface drainage basin. The all year round flowing (perennial) rivers are linked to groundwater outcrops from faults/fractures and contact zones. Consequently, larger percentage of annual rainwater usually leaves the basin in form of runoff and base flow. Therefore, the basin is categorized as a donor basin but with suspected subsurface water input at its northeastern axis.

Paleocurrents and depositional environments of deep water conglomerates in the Cambro-Ordovician Cap Enragé Formation, Quebec Appalachians

1979 ◽  
Vol 16 (7) ◽  
pp. 1375-1387 ◽  
Author(s):  
Barry A. Johnson ◽  
Roger G. Walker
Keyword(s):  
Deep Water ◽  
Flow Direction ◽  
Depositional Environments ◽  
The West ◽  
Submarine Fan ◽  
Local Flow ◽  
Flow Directions ◽  
La Jolla ◽  
Contrast Flow

The Cap Enragé conglomerates are deep water, resedimented types associated with pebbly and massive sandstones. They resemble other deep water conglomerates in Quebec, especially those at Lévis-Lauzon, L'Islet Wharf, and Grosses Roches. All of these conglomerates were derived from a carbonate shelf to the northwest, and flow directions at Lévis and L'Islet are dominantly southward. By contrast, flow directions at Grosses Roches are to the west and southwest, suggesting deflection of conglomeratic flows by a topographic obstruction.In the Cap Enragé, only published flow directions from sandstones suggest flow toward south and southeast. One published conglomeratic flow direction indicates southwestward flow. Our paleoflow work on the entire outcrop length of the Cap Enragé conglomerates demonstrates dominantly westward and southwestward flow, reinforcing the idea of a topographic obstruction deflecting flows.We have demonstrated some consistent horizontally-fining facies relationships in the conglomerates. Beginning with massive, coarse cobble–boulder conglomerates, there are horizontal passages into finer conglomerates with crude stratification shown up by rows of cobbles and then pebbles, and finally into well stratified coarse sandstones with layers of granules and pebbles. Compared with local flow directions, these horizontally-fining relationships occur in upstream, downstream, and lateral directions.We suggest that southeastward, downslope-flowing currents were forced to swing southwestward by an obstruction, and hence the entire Cap Enragé Formation was deposited in a broad depression or channel trending parallel to the base of slope. Within this overall interpretation, we suggest that the conglomerate members of the Cap Enragé were deposited in meandering talweg channels, similar to those of the modern La Jolla submarine fan channel. Upstream-, downstream-, and laterally-fining facies sequences may be related to the filling of large scours within the talweg, or to facies changes from the talweg to adjacent terraces.

Questioning the president: Examining gender in the White House press corps

Journalism ◽  
2016 ◽  
Vol 19 (4) ◽  
pp. 519-535 ◽  
Author(s):  
Lindsey Meeks
Keyword(s):  
Content Analysis ◽  
Foreign Trade ◽  
Potential Influence ◽  
President Obama ◽  
Women Journalists ◽  
Men And Women ◽  
Political Issues ◽  
White House ◽  
Press Corps ◽  
Before And After

In 2014, President Barack Obama made history by only calling upon women journalists during a domestic news conference with the White House press corps. To capitalize on and examine this critical first in journalism, this study analyzed the potential influence of a journalist’s gender in White House press corps news conferences with President Obama a year before and a year after the all-female conference. The content analysis examined what political issues journalists emphasized in presidential news conferences and whether these issue emphases varied (a) by journalists’ gender and (b) before and after the all-female conference. Results revealed that, to some extent, men and women emphasized different issues. Furthermore, there were marked shifts after the all-female conference. First, women were called upon more often. Second, women emphasized several issues more than men. In particular, women became predominant on questions dealing with so-called ‘masculine’ or ‘hard news’ issues, for example, macroeconomics and foreign trade. This work suggests that gender, in all of its permutations – be it the journalist’s gender, the gendering of issues, or the gendering of occupational spaces – matters and may affect journalists’ lines of questioning.

scholarly journals HURRICANE ALICIA: STORM SURGES AND SHORE PROCESSES

1984 ◽  
Vol 1 (19) ◽  
pp. 18
Author(s):  
R.P. Savage
Keyword(s):  
Additional Data ◽  
Storm Surges ◽  
Barrier Islands ◽  
Water Levels ◽  
Beach Erosion ◽  
Field Evidence ◽  
Before And After ◽  
Maximum Water ◽  
Flow Directions ◽  
The Right

Hurricane Alicia moved inland over the Texas coast during the night of August 17, 1983 creating waves and surges in the Gulf of Mexico and adjacent bays. Waves eroded beaches and dunes and surges overtopped low-lying areas of barrier islands and inland areas adjacent to the bays behind the barriers. A three-day survey of field evidence of water levels and flow directions was carried out one week after the storm. Physical evidence, such as the elevation of debris lines, water marks in buildings and debris caught on fences was used along with additional data from tide gages operating in the area to estimate the maximum flood levels and flow directions associated with the storm. Before and after aerial photography was used to obtain data on beach recession, retreat of the vegetation line behind the beach and extent of oyerwash deposits. The evidence gathered shows that the barrier islands were overtopped from front-to- back in some areas and from back-to-front in other areas with quite different results. There was little or no beach erosion to the left of the storm as it came ashore; however, serious beach erosion occurred for 18 miles (29.0 km) to the right of the storm and there was significant erosion for 55 miles (88.5 km) to the right of the storm. Maximum water levels in the Gulf, including the effects of normal tides and storm effects, were 9 to 11 feet (2.74 to 3.35 m) and maximum water levels along the nothern portion of Galveston Bay were 11 to 14 feet (3.35 to 4.27 m).

Influence of Bubble Sizes on Ozone Solubility Utilization and Disinfection

1985 ◽  
Vol 17 (6-7) ◽  
pp. 1081-1090 ◽  
Author(s):  
Mansoor Ahmad ◽  
Shaukat Farooq
Keyword(s):  
Gas Flow ◽  
Bacterial Population ◽  
Flow System ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Before And After ◽  
Standard Plate ◽  
Plate Counts ◽  
Bubble Sizes ◽  
Ozone Contactor

A disinfection study was carried out in a continuous flow system employing different sizes of ozone bubbles to determine their effects on solubility of ozone, its utilization and inactivation of microorganisms. The bubble sizes were varied by changing the porosity of the diffusers and ozone flow rates through the ozone contactor. Natural bacterial population (standard plate counts) present in the secondary wastewater effluent, was enumerated before and after ozonation. It was found that for a given concentration of ozone at a constant gas flow rate, decrease in bubble sizes resulted in an increase in ozone residual and degree of inactivation of organisms inspite of a decrease in ozone utilization by the wastewater.

Groundwater flow systems in the crystalline rocks of the Okanagan Highland, British Columbia

1968 ◽  
Vol 5 (4) ◽  
pp. 813-824 ◽  
Author(s):  
D. W. Lawson
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Flow ◽  
Flow System ◽  
Crystalline Rock ◽  
Crystalline Rocks ◽  
Two Dimensional ◽  
Local Flow ◽  
Groundwater Flow Systems ◽  
Flow Systems ◽  
Two Dimensional Flow

An investigation of the groundwater flow systems associated with the most prominent topographic expression in the Okanagan Highland (a U-shaped valley) revealed that the hydraulic conductivity of the crystalline rock varies exponentially with depth, and that the local flow systems within the upper 125 to 150 ft of the crystalline rock conduct an estimated 10 to 17 Imperial gallons per day per foot thickness in a two-dimensional flow system. These local flow systems are quantitatively the most significant in the Okanagan Highland.

scholarly journals Origin and Residence Time of Groundwater in the Shallow Coastal Aquifer of Eastern Dahomey Basin, Southwestern Nigeria, Using δ18O and δD Isotopes

2020 ◽  
Vol 10 (22) ◽  
pp. 7980
Author(s):  
Jamiu A. Aladejana ◽  
Robert M. Kalin ◽  
Ibrahim Hassan ◽  
Philippe Sentenac ◽  
Moshood N. Tijani
Keyword(s):  
Residence Time ◽  
Vadose Zone ◽  
Major Ions ◽  
Dry Season ◽  
Global Network ◽  
Shallow Aquifer ◽  
Seasonal Effect ◽  
Water Types ◽  
Groundwater Samples ◽  
Dahomey Basin

This study employed stable isotopes of δ18O and δ2H in conjunction with other hydrological parameters to understand the origin, inferred residence time, and seasonal effect of groundwater in the shallow aquifers of the eastern Dahomey Basin. A total of 230 groundwater samples (97 in the wet season and 133 in the dry season) were collected from the borehole and shallow aquifer between May 2017 and April 2018. Groundwater analysis included major ions and δ18O and δ2H, isotopes data in precipitation from three selected Global Network of Isotope in Precipitation (GNIP) stations across West Africa, Douala in Cameroon, Cotonou in Republic of Benin, and Kano in Nigeria were used in comparative analysis. Results of the hydrochemical model revealed Ca-HCO3 and Na-Cl as dominant water types with other mixing water types such as Ca–SO4, Ca–Cl, Na–SO4, and K–Mg–HCO3, which characterised early stage of groundwater transformation as it infiltrates through vadose zone into the aquifer. δ18O and δ2H precipitation data from the three stations plotted along with the groundwater samples indicate recent meteoric water origin, with little effect of evaporation during the dry season. The plot of Total Dissolved Solids (TDS) against δ18O showed clustering of the water samples between the recharge and the evaporation zone with dry season samples trending towards increased TDS, which is an indication of the subtle effect of evaporation during this period. Tracing groundwater types along the flow paths within the basin is problematic and attributed to the heterogeneity of the aquifer with anthropogenic influences. Moreover, a comparison of the δ18O and δ2H isotopic compositions of groundwater and precipitation in the three selected stations, with their respective deuterium excess (D-excess) values established low evapotranspiration induced isotope enrichment, which could be due to higher precipitation and humidity in the region resulting in low isotope fractionation; hence, little effect of seasonal variations. The study, therefore, suggested groundwater recharge in the shallow aquifer in the eastern Dahomey Basin is of meteoric origin with a short residence time of water flows from soils through the vadose zone to the aquifers.

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