Temat: groundwater flow - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Numerical simulation of the quaternary aquifer groundwater flow of the northern Vistula Delta Plain
Autorzy:: Szpakowski, W.
Tematy:: groundwater flow
numerical calculations
Modflow code
groundwater resources; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1933155.pdf Link otwiera się w nowym oknie
Opis:: Results of Quaternary aquifer flow calculations are presented for the Vistula Delta Plain and the southern Kashubian Lakeland edge zone. The Quaternary level is one of the most important water supply resources for the city of Gdansk. The numerical simulations of groundwater flow were performed using the Modflow and Modpath codes and the Groundwater Modeling System (GMS 3.1) package. Calculations representing the state prior to the launch of the Lipce intake were performed under steady state conditions. The model was calibrated, which enabled simulation of groundwater flow under transient conditions. Calculation for the years 1969-1985 have shown the evolution of a Quaternary aquifer depression cone. The inflow from river Dead Vistula to the Quaternary aquifer is recognized through particle path solution for a selected water particle. The numerical solution has confirmed the observed increase of Cl- ions in the Grodza Kamienna intake after 1969.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Calculating effective conductivity of heterogeneous soils by homogenization
Autorzy:: Szymkiewicz, A.
Tematy:: effective conductivity
soil heterogeneity
groundwater flow
homogenization; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Powiązania:: https://bibliotekanauki.pl/articles/241053.pdf Link otwiera się w nowym oknie
Opis:: The paper concerns effective conductivity of a heterogeneous soil composed of two materials characterized by different hydraulic conductivities. According to the homogenization theory the effective conductivity is obtained from the solution of an elliptic equation for a single representative elementary volume. A numerical algorithm to solve this equation is described. Examples of calculations for periodic media with inclusions of various shapes are presented. Influence of volumetric fraction, arrangement, continuity and conductivity ratio of the two materials on the effective conductivity is investigated. Numerical results are compared with some analytical estimations available in the literature.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: The influence of groundwater discharge on the runoff of an Arctic stream (Ebba River, Central Spitsbergen)
Autorzy:: Marciniak, M.
Dragon, K.
Tematy:: active layer
groundwater flow
Svalbard
Arctic region; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2062982.pdf Link otwiera się w nowym oknie
Opis:: The article presents investigation of groundwater occurrence in the Ebba River catchment located in central Spitsbergen (Petuniabukta region). It was recognized that groundwater occurs there seasonally in the summer melting season when the melting of active layer take place and enable flow of groundwater. Using data from four groups of piezometers located in different parts of the valley the hydrogeological parameters that characterize this shallow aquifer (thickness of the active layer, hydraulic conductivity, groundwater level fluctuations) were recognized. Using Darcy’s low the amount of water that recharge Ebba River was calculated using field data. This calculation enabled more precise estimation of other component of Ebba River recharge (surface and overland water inflow, recharge from glaciers). These calculations were confirmed by interpretation of groundwater and surface water chemistry differentiation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Assessment of the Groundwater in Erbil Basin with Support of Visual MODFLOW
Autorzy:: Mustafa, Jwan Sabah
Mawlood, Dana Khider
Tematy:: analyzing the groundwater
Erbil Basin
groundwater flow modeling
visual MODFLOW; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/59114462.pdf Link otwiera się w nowym oknie
Opis:: Groundwater stands as a crucial lifeline in numerous regions across the globe, a significance magnified in water-scarce locales like the Middle East. With depleting water resources exacerbated by global climate change, the imperative for sustainable groundwater management becomes increasingly urgent. This research employs a groundwater flow modeling approach, utilizing Visual MODFLOW (version 4.6.0.166), to scrutinize the present state and future security risks of groundwater resources in the Erbil basin. A distinct aspect of this study involves investigating the interaction between the groundwater aquifers of Greater Zab and Lesser Zab Rivers, along with an exploration of the Erbil aquifers, rivers interaction and recharge zones as a second novelty in this research. The model, calibrated for heterogenous anisotropic unconfined aquifer transient conditions, exhibits a high correlation coefficient (CC) of 0.997 during calibration and 0.985 in the validation process respectively. Findings indicate a general groundwater flow direction from northeast to southwest in the Erbil basin, aligning with surface observations. Despite groundwater aquifers supplying only 55% of the current water demand from the existing wells, the computed balance reveals river leakages of 33,432 m3/day into the aquifers. The study forecasts a substantial increase in the dry area of the groundwater aquifer under climate change scenarios, especially when recharge rates diminish. To mitigate these impacts, the study recommends preventing illegal well drilling and implementing continuous monitoring using distributed sensors. The insights gleaned from this research are anticipated to furnish essential information for sustainable planning and effective management of groundwater resources in the Erbil basin and its environs.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Groundwater mapping of urban and coastal areas in Brunei
Autorzy:: Abidin, Hakimmi
Azffri, Siti Lieyana
Nirus, Emelia
Suhip, Asri
Jaya, Afiq Aiman
Gödeke, Stefan Herwig
Tematy:: Brunei
groundwater contour map
groundwater depth
groundwater flow path
submarine groundwater discharge
SGD; Pokaż więcej
Wydawca:: Instytut Technologiczno-Przyrodniczy
Powiązania:: https://bibliotekanauki.pl/articles/58906929.pdf Link otwiera się w nowym oknie
Opis:: Groundwater mapping plays an important role in effective water resource management, sustainable development, and environmental protection. In the tropical Brunei Darussalam (north Borneo Island), groundwater mapping is yet to be provided. The aim of the study is to provide groundwater mapping of Brunei, particularly for the urban and coastal areas of the Brunei-Muara capital district. The study uses a GIS interpolation technique to generate a groundwater contour map based on groundwater data from 572 sacrificial boreholes located in the study area. Remote sensing data and published maps from secondary sources were digitised in ArcGIS software to produce thematic layers for further hydrological evaluations. Results showed that groundwater levels in the study area are generally high and shallow, ranging from 0 to 18 m below ground level with a mean value of 2.9 m. According to the evaluation of geo-thematic layers and groundwater contours, groundwater flows towards the South China Sea in the coastal areas and towards the Brunei River further inland. Hydraulic gradients towards the South China Sea also vary between 0.004 and 0.08. Thus, assuming surface aquifer thickness in the weathered zone between 10 to 20 m, hydraulic conductivities ranges from 1∙10-5 to 1∙10-4 m∙s-1, a submarine groundwater discharge (SGD) flux between 4.7∙10-7 to 4.0∙10-4 m3 ∙s-1 per unit width can be estimated for the shallow aquifer. This study provides valuable insights into the groundwater system dynamics so important, which are critical for its future utilisation and protection, aiming to contribute to the national water security in Brunei Darussalam.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Groundwater conditions along the seawater/freshwater interface on a volcanic island and a depositional area in Japan
Autorzy:: Marui, A.
Tematy:: submarine groundwater discharge
seawater/freshwater interface
groundwater flow
far-east area; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2058825.pdf Link otwiera się w nowym oknie
Opis:: Fresh groundwater comes in contact with seawater at the downstream end of its flow system. Most previous work has discussed the shape of the seawater/freshwater interface on the basis of Ghyben-Herzberg’s law. The groundwater, however, pushes the seawater farther offshore side than predicted by the law, giving rise to freshwater flows even below the bottom of the sea. A previous study found that the distribution of submarine groundwater discharge and the point of the seawater/freshwater interface on the marine floor are closely related. The cross-sectional shape of the interface onshore is clarified by using electrical tomography and observation of groundwater and soil samples taken from observation wells located in the coastal area (by a volcanic island and associated deposits). In both fields, diving was carried out to find the submarine groundwater discharge on the sea-floor and to take water samples. From the analysis of the water discharged on the marine floor and/or electric conductivity measurements in the marine sands, it is shown the freshwater flows (discharges) along the interface, even in the submarine deposits. The understanding of groundwater flows at the downstream end of the groundwater flow system (from mountainous to marine) will facilitate the development of water resources and the evaluation of environments.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Vertical nitrate migration and denitrification zones in a regional recharge area (Lwówek region, Poland)
Autorzy:: Dragon, Krzysztof
Górski, Józef
Burghardt, Diana
Tematy:: nitrate contamination
enitrification
groundwater flow pattern
nitrogen isotopes
sediment geochemistry; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2149469.pdf Link otwiera się w nowym oknie
Opis:: We examine the influence of groundwater flow patterns and denitrification on nitrate migration in a regional recharge zone. It has been shown that nitrate contamination has a different behaviour in regions where groundwater is exploited (where deep percolation of nitrate takes place) than where natural gradients exist (with no deep aquifer zone contamination). Multicomponent chemical tracers and isotopic methods were used in the investigation. A contaminant plume was discovered in shallow parts of the aquifer which percolated into deeper parts of the flow system in those regions with a downwards gradient induced by groundwater withdrawal, where the influence of denitrification was limited. Local conditions leading to intense denitrification, i.e., local changes in geological conditions (low-permeability silt intercalations), were also documented. Therefore, vertical changes in groundwater chemistry should be examined to ensure groundwater resource management and protection, as these are extremely important in regional recharge zones with a downwards gradient.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Recharge of Gdańsk municipal groundwater intakes on the Vistula Delta Plain (Northern Poland)
Autorzy:: Szpakowski, W.
Tematy:: Vistula Delta Plain Quaternary aquifer
Modflow
groundwater intake
numerical calcutation
groundwater flow; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2058832.pdf Link otwiera się w nowym oknie
Opis:: Results of the Vistula Delta Plain Quaternary recharge analysis are presented in this paper. This region is situated south of Gdańsk city near the Bay of Gdańsk. There are two municipal intakes situated on the Vistula Delta Plain: Lipce and Grodza Kamienna. Different exploitation of the municipal intakes is considered. The numerical calculations are made for the pre- 1969 period before the Lipce intake started discharging the Quaternary aquifer in the steady-state conditions and for the 15 years period after the opening of the Lipce intake, in the transient conditions. The results of calculations of the natural state of the Vistula Delta Plain Quaternary aquifer are also presented. The numerical calculations were carried out using the Modflow and Modpath code in Groundwater Modelling System (GMS 2.1) package. Presented results of numerical calculations show that the Quaternary aquifer exploited by groundwater intakes Lipce and Grodza Kamienna is connected with inflow from the Martwa Wisła River into the Vistula Delta Plain Quaternary aquifer and confirm the Quaternary aquifer groundwater flow evaluation based on Cl– ions concentration in the observation wells.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: The velocity oriented approach revisited
Autorzy:: Nawalany, M.
Zijl, W.
Tematy:: velocity oriented approach
continuity of water flux
groundwater flow modeling; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2063027.pdf Link otwiera się w nowym oknie
Opis:: A great deal of hydrogeological situations requires an extremely accurate calculation of the 3-dimensional groundwater discharge rates in the subsoil. Examples are: hydrology of wetlands, water balances of aquatic ecosystems depending on groundwater recharge, river-groundwater interaction, advective transport of pollution underneath waste disposal sites, particle trajectories in aquifer-aquitard systems with contrasting heterogeneities and many others. Numerical determination of the vertical groundwater velocity is a notoriously difficult problem. In nature this component may be two or three orders of magnitude smaller than the horizontal velocity components. In such cases application of Darcy’s law to the numerically calculated hydraulic heads obtained from a finite difference or finite element model may lead to relatively inaccurate vertical velocities. More specifically, when estimating vertical velocity components in cases where the Dupuit approximation – negligible vertical head gradient – holds, numerical differentiation of hydraulic heads yields zero vertical velocity. In the 1980s of the last century Zijl and Nawalany proposed to invert the order of calculating the velocity field by eliminating the head from Darcy’s law and to consider the Darcy velocity as the primary variable. For 2-dimensional flow this was already common practice and the challenge was a 3-dimensional extension, which was called the Velocity Oriented Approach (VOA). In two dimensions such methods were conventionally based on a stream function as primary variable. However, at that time application of a 3D stream function was not feasible and, therefore, the Darcy velocity itself was considered as the primary variable. This approach has been proven to yield a high accuracy for all three components of the specific discharge, including the relatively small vertical component, especially in cases where the subsoil is smoothly heterogeneous in the horizontal directions. In the 1990s the mixed-hybrid finite element method was developed. The physical interpretation of this method shows the way how to liberate the VOA from its smoothness requirement by introduction of a practical applicable 3D stream function. In conclusion, the velocity oriented approach indicates a change in paradigm regarding the accurate calculation of specific discharge in groundwater flow.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Aktualne warunki hydrogeologiczne obszaru Dąbrowa-Sienna (Pogórze Rożnowskie)
Recent hydrogeological conditions of the Dąbrowa-Sienna area (Rożnów foothill)
Autorzy:: Zawiślan, Justyna
Opis:: Badania hydrologiczne prowadzone na przełomie listopada i grudnia 2019 r. dowodzą, że w na obszarze Dąbrowa–Sienna zlokalizowanym w SE cześć Pogórza Rożnowskiego w Karpatach zewnętrznych zwierciadło wód podziemnych pierwszego poziomu zalega na wysokości między 270 a 570 m n. p. m. i na średniej głębokości wynoszącej 3,8 m pod powierzchnią trenu. Najgłębiej (do 21,6 m p.p.t.) zwierciadło wód podziemnych zalega w strefie występowania słabo przepuszczalnych łupków warstw krośnieńskich należących do serii śląskiej. Na badanym obszarze obserwuje się przepływy podziemne o kierunkach od szczytów wzniesień do dolin potoków oraz w kierunku Jeziora Rożnowskiego. Potoki mają charakter drenujący.
Hydrogeological studies conducted at the turn of November and December 2019 in Dąbrowa– Sienna area (SE part of Rożnów Foothill) in the Outer Carpathians proved that the groundwater table is located between 270 and 57 m a.s.l. and has a mean depth of 3.7 m under the surface. The deepest part of groundwater table is located 21.6 m under the surface in the zone build of impermeable shales of the Krosno beds belongs to Silesian Nape. The dominant groundwater flow directions are from the tops of the hills towards the stream valleys and towards the Rożnów Lake. The streams represent a gaining type.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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