Withdrawals, water levels, and specific conductance in the Chicot aquifer system in southwestern Louisiana, 2000-03

Author(s):  
John K. Lovelace ◽  
Jared W. Fontenot ◽  
C. Paul Frederick
2018 ◽  
Vol 7 (4) ◽  
pp. 191
Author(s):  
Sherwan Sh. Qurtas

Recharge estimation accurately is crucial to proper groundwater resource management, for the groundwater is dynamic and replenished natural resource. Usually recharge estimation depends on the; the water balance, water levels, and precipitation. This paper is studying the south-middle part of Erbil basin, with the majority of Quaternary sediments, the unconfined aquifer system is dominant, and the unsaturated zone is ranging from 15 to 50 meters, which groundwater levels response is moderate. The purpose of this study is quantification the natural recharge from precipitation. The water table fluctuation method is applied; using groundwater levels data of selected monitoring wells, neighboring meteorological station of the wells, and the specific yield of the aquifers. This method is widely used for its simplicity, scientific, realistic, and direct measurement. The accuracy depends on the how much the determination of specific yield is accurate, accuracy of the data, and the extrapolations of recession of groundwater levels curves of no rain periods. The normal annual precipitation there is 420 mm, the average recharge is 89 mm, and the average specific yield is around 0.03. The data of one water year of 2009 and 2010 has taken for some technical and accuracy reasons.


Author(s):  
Soo-Hyoung Lee ◽  
Jae Min Lee ◽  
Sang-Ho Moon ◽  
Kyoochul Ha ◽  
Yongcheol Kim ◽  
...  

AbstractHydrogeological responses to earthquakes such as changes in groundwater level, temperature, and chemistry, have been observed for several decades. This study examines behavior associated with ML 5.8 and ML 5.1 earthquakes that occurred on 12 September 2016 near Gyeongju, a city located on the southeast coast of the Korean peninsula. The ML 5.8 event stands as the largest recorded earthquake in South Korea since the advent of modern recording systems. There was considerable damage associated with the earthquakes and many aftershocks. Records from monitoring wells located about 135 km west of the epicenter displayed various patterns of change in both water level and temperature. There were transient-type, step-like-type (up and down), and persistent-type (rise and fall) changes in water levels. The water temperature changes were of transient, shift-change, and tendency-change types. Transient changes in the groundwater level and temperature were particularly well developed in monitoring wells installed along a major boundary fault that bisected the study area. These changes were interpreted as representing an aquifer system deformed by seismic waves. The various patterns in groundwater level and temperature, therefore, suggested that seismic waves impacted the fractured units through the reactivation of fractures, joints, and microcracks, which resulted from a pulse in fluid pressure. This study points to the value of long-term monitoring efforts, which in this case were able to provide detailed information needed to manage the groundwater resources in areas potentially affected by further earthquakes.


2018 ◽  
Author(s):  
Nicholas D. Woodman ◽  
William G. Burgess ◽  
Kazi Matin Ahmed ◽  
Anwar Zahid

Abstract. The coupled poro-mechanical behaviour of geologic-fluid systems is fundamental to numerous processes in structural geology, seismology and geotechnics but is frequently overlooked in hydrogeology. Substantial poro-mechanical influences on groundwater head have recently been highlighted in the Bengal Aquifer System, however, driven by terrestrial water loading across the Ganges-Brahmaputra-Meghna floodplains. Groundwater management in this strategically important fluvio-deltaic aquifer, the largest in south Asia, requires a coupled hydro-mechanical approach which acknowledges poro-elasticity. We present a simple partially-coupled, one-dimensional poro-elastic model of the Bengal Aquifer System, and explore the poro-mechanical responses of the aquifer to surface boundary conditions representing hydraulic head and mechanical load under three modes of terrestrial water variation. The characteristic responses, shown as amplitude and phase of hydraulic head in depth profile and of ground surface deflection, demonstrate (i) the limits to using water levels in piezometers to indicate groundwater recharge, as conventionally applied in groundwater resources management; (ii) the conditions under which piezometer water levels respond primarily to changes in the mass of terrestrial water storage, as applied in geological weighing lysimetry; (iii) the relationship of ground surface vertical deflection to changes in groundwater storage; and (iv) errors of attribution that could result from ignoring the poroelastic behaviour of the aquifer. These concepts are illustrated through application of the partially-coupled model to interpret multi-level piezometer data at two sites in southern Bangladesh. There is a need for further research into the coupled responses of the aquifer due to more complex forms of surface loading, particularly from rivers.


2018 ◽  
Vol 55 (7) ◽  
pp. 677-708 ◽  
Author(s):  
David R. Sharpe ◽  
André J.-M. Pugin ◽  
Hazen A.J. Russell

The Laurentian trough (LT), a depression >100 km long, >3000 km2 in area, and 100 m deep at the base of the Niagara Escarpment, extends from within Georgian Bay to Lake Ontario. It has a complex erosional history and is filled and buried by up to 200 m of interglacial and glacial sediment. The primary depression fronts a cuesta landscape and is attributed to differential erosion by fluvial, glacial, and glaciofluvial processes, exposing Ordovician rocks along the Canadian Shield margin. The fill succession includes sediments from the last two glacial periods (Illinoian, Wisconsinan) and the intervening interglacial time (Sangamonian), a poorly dated succession with at least three regional unconformities. A subaerial (interglacial, Don Formation) unconformity relates to low base level mainly preserved in lows of the LT, succeeded by a long period of rising water levels and glaciolacustrine conditions as ice advanced into the Lake Ontario basin. A second unconformity, within the Thorncliffe Formation, is the result of rapid channel erosion to bedrock, forming an ∼north–south network filled with coarse-grained glaciofluvial, transitional to fine-grained glaciolacustrine subaqueous fan sediment. The overlying drumlinized Newmarket Till, up to 50 m thick, is a distinct regional unit with a planar to undulating base. A third unconformity event eroded Newmarket Till, locally truncating it and underlying sediment to bedrock. Three younger sediment packages, Oak Ridges Moraine (channel and ridge sediment), Halton, and glaciolacustrine overlie this erosion surface. Significant regional aquifers are hosted within the LT. Upper Thorncliffe Formation sediments, north–south glaciofluvial channel–fan aquifers, are protected by overlying mud and Newmarket Till aquitards. Similarly, Oak Ridges Moraine sediments comprise a north–south array of glaciofluvial channel–fans and east–west fan aquifers, locally covered by silt–clay rhythmite and till aquitards.


2018 ◽  
Vol 37 (1) ◽  
pp. 113-120
Author(s):  
Habiba Majour ◽  
Azzedine Hani ◽  
Larbi Djabri

Abstract The potentiometer area in the Annaba basin, covering an area of 264 km2, has declined considerably since 1995. The analysis of the chronological hydrographs (1991–2009) of the piezometric observations shows that this decline is related to about twenty years (20 years) drought that began in 1991. To synthesize hydrological data and study regional changes in aquifer interactions caused by changes in discharge, and determine the contamination of aquifers by salty intrusion in coastal areas, and making forecasts by the year 2023, a multi-layered transient model as well as a solute transport model has been developed. The groundwater flow was modelled using the finite difference method with a horizontal dimension of 500 × 500 m for the cells. The model consists of two layers, the first corresponding to the alluvial phreatic aquifer and the second to the deep confined aquifer, and is calibrated against the steady state groundwater heads recorded before 1996. Model verification was done by history matching over the period 1991–2009. Under steady-state conditions, the correspondence between simulated and observed water levels is generally good (average difference of 0.4 m). For the deep aquifer, the simulated time-series hydrographs closely match the recorded hydrographs for most of the observation wells. For the alluvial aquifer, the recorded hydrographs cover only a short time period, but they are reproduced. The model indicates that groundwater pumping induced a decrease in natural discharge, a downward leakage in most of the basin and a continual water-level decline. The model has also been applied to the analysis of recharge impact. Simulating the behaviour of the system over the period 1991–2009 without pumping indicated small changes in hydraulic head. These results show that the groundwater reservoir has a low recharge, but excellent hydraulic properties. A solute-transport model was used to study aquifer contamination from salty intrusion in coastal sectors; it was extended to the year 2023 by simulating an optimistic hypothesis that maintains present pumping until 2023. The model indicates that the head decrease of the alluvial phreatic and deep confined aquifers will be 4 m and 5 m respectively. The solute concentration in the deep confined aquifer will increase from 1 gꞏdm−3 (prior 2009) to 5 gꞏdm−3 in 2023.


2020 ◽  
pp. 161-199
Author(s):  
Nadhir Al-Ansari ◽  
Sabbar Saleh ◽  
Twana Abdullahand ◽  
Salwan Ali Abed

Insufficiency of water resources in the Middle East Region represents vital factors that influence the stability of the region and its progress. Expectations indicate that the condition will be dimmer and more complicated, especially in Iraqi territory. Iraq, which is situated in the Middle East, it covers an area of 433,970 square kilometers and populated by about 32 million inhabitants. Iraq greatly relies in its water resources on the Tigris and Euphrates Rivers as a surface water resources, and several productive groundwater aquifers in which from the hydrogeological point of view divided into several major aquifer units including Foothill, Al-Jazira, Aquifer System, Mandali-Badra-Teeb, Mesopotamian and Desert Aquifer system. Recently, Iraq is suffering from water shortage problems. This is due to external and internal factors affecting the water quality of water resources; they are controlled and uncontrolled factors. The uncontrolled factors are climate change and its consequences, such as reduction of precipitation and temperature increasing. The controlled factors have a significantly negative influence on water resources, but their effects involve more specific regions. The controlled factors are mainly represented by building dams and irrigation projects within the upper parts of the Tigris and Euphrates catchments, Al-Tharthar Scheme, waste water, solid wastes and wastes from wars, which has a significant effect on surface water in Iraq because about 80% of the water supply to Euphrates and Tigris Rivers come from Turkey. In addition, the pressures resulting from the high demand for water resources, and the continued decline in their quantity rates have led to major changes in the hydrological condition in Iraq during the past 30 years. The decrease in surface water levels and precipitation during these three decades reflects the drop in the levels of water reservoirs, lakes, and rivers to the unexpected levels. The level of main country’s water source, Tigris, and Euphrates Rivers has fallen to less than a third of its natural levels. As storage capacity depreciates, the government estimates that its water reserves have been reduced precariously. According to the survey from the Ministry of Water Resources, millions of Iraqi people have faced a severe shortage of drinking water. Since of the importance of water for human life and the need to monitor temporal and spatial changes in quality and quantity, there is a need to develop a general Iraqi Water Quality Index (Iraq WQI) to monitor surface water and groundwater and classify it into five categories, very good, good, acceptable, bad and very bad, in terms of suitability for domestics, irrigation and agriculture depending on the Iraqi and WHO standards for drinking water. In addition, strict establishment for the regular quantitative monitoring surface water and groundwater setting and processes. Prospects are more negative for all riparian countries. This implies that solving these problems requires actual and serious international, regional, and national cooperation to set a prudent plan for water resources management of the two basins. Iraq being the most affected country should seriously set a prudent, scientific, and strategic plan for the management and conservation of its water resources. Keywords: Pollution, Water Quality, Waste, Surface water, Groundwater, Iraq.


2021 ◽  
Vol 14 (1) ◽  
pp. 413
Author(s):  
Rodrigo Valdés-Pineda ◽  
Pablo A. Garcia-Chevesich ◽  
Alberto J. Alaniz ◽  
Héctor Venegas-Quiñonez ◽  
Juan B. Valdés ◽  
...  

Several studies have focused on why the Aculeo Lagoon in central Chile disappeared, with a recent one concluding that a lack of precipitation was the main cause, bringing tremendous political consequences as it supported the argument that the government is not responsible for this environmental, economic, and social disaster. In this study, we evaluated in detail the socio-economic history of the watershed, the past climate and its effects on the lagoon’s water levels (including precipitation recycling effects), anthropogenic modifications to the lagoon’s water balance, the evolution of water rights and demands, and inaccurate estimates of sustainable groundwater extraction volumes from regional aquifers. This analysis has revealed novel and undisputable evidence that this natural body of water disappeared primarily because of anthropogenic factors (mostly river deviations and aquifer pumping) that, combined with the effects of less than a decade with below-normal precipitation, had a severe impact on this natural lagoon–aquifer system.


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