Modeling of groundwater flow velocity and aquifer recharge in a Cenozoic multi-aquifer system – a case study from Eastern Brandenburg (Germany)

2020 ◽  
Author(s):  
Silvio Janetz ◽  
Christoph Jahnke ◽  
Frank Wendland ◽  
Hans-Jürgen Voigt
Keyword(s):  
Groundwater Flow ◽  
Groundwater Resources ◽  
Turnover Time ◽  
Aquifer Recharge ◽  
Deep Groundwater ◽  
Near Surface ◽  
Aquifer System ◽  
Deep Aquifers ◽  
Regional Flow ◽  
Flow Processes

<p>In recent years, deep aquifers (> 50 m below ground level) have become increasingly interesting for the supply of drinking and irrigation water or geothermal use. Understanding the regional flow processes between near-surface and deep aquifer systems is an important criterion for the sustainable management of deep groundwater resources. However, hydrogeological conditions, regional flow rates and aquifer recharge in deep aquifers are largely unknown in many cases. The aims of the present study are therefore to determine (i) groundwater flow velocities in a Cenozoic multi-aquifer system, and (ii) proportion of aquifer recharge into the individual Cenozoic aquifers and timescales to completely replace water in the Cenozoic aquifers (turnover time).  </p><p>The numerical study was carried out in three adjacent groundwater catchment areas in the region of Eastern Brandenburg. In a first step, a hydrogeological 3D model of the entire Cenozoic aquifer system (85 km × 73 km and down to a depth of 0.5 km) was developed, which comprises up to 12 unconsolidated sandy aquifers and 10 confining units (glacial tills, silts and clays). In a second step, a steady-state flow modelling was performed including calibration using natural hydraulic head data from both regional main and deep aquifers.</p><p>The modeling results show that the average groundwater flow velocities decrease from 20-50 m/a in the near-surface Pleistocene main aquifers to 1-2 m/a in the deep Oligocene aquifers. At the same time, the aquifer recharge in the aquifer system decreases substantially with increasing depth. Depending on the catchment geology, the Pleistocene main aquifers are recharged by 65-70 % of infiltration water, while the aquifer recharge of the deep Oligocene aquifers is only 4.5-9.5 %. The calculations of turnover time indicate that the time periods to completely flush the deep aquifers are very long (approx. between 90 and 4600 years). The results thus allow a first quantification of the flow processes between near-surface and deep aquifers as well as the identification of flow paths to develop a utilization concept for deep groundwater resources in the region of Eastern Brandenburg.</p>

3D modelling of a hydrological structure combining spatial data science and geophysics: Application to a coastal aquifer system in the island of Crete, Greece

2021 ◽  
Author(s):  
Emmanouil Varouchakis ◽  
Leonardo Azevedo ◽  
João L. Pereira ◽  
Ioannis Trichakis ◽  
George P. Karatzas ◽  
...  
Keyword(s):  
Climate Change ◽  
Groundwater Flow ◽  
Spatial Data ◽  
Coastal Aquifer ◽  
Data Science ◽  
Flow Model ◽  
Groundwater Resources ◽  
Geostatistical Simulation ◽  
Groundwater Flow Model ◽  
Aquifer System

<p>Groundwater resources in Mediterranean coastal aquifers are under threat due to overexploitation and climate change impacts, resulting in saltwater intrusion. This situation is deteriorated by the absence of sustainable groundwater resources management plans. Efficient management and monitoring of groundwater systems requires interpreting all sources of available data. This work aims at the development of a set of plausible 3D geological models combining 2D geophysical profiles, spatial data analytics and geostatistical simulation techniques. The resulting set of models represents possible scenarios of the structure of the coastal aquifer system under investigation. Inverted resistivity profiles, along with borehole data, are explored using spatial data science techniques to identify regions associated with higher uncertainty. Relevant parts of the profiles will be used to generate 3D models after detailed Anisotropy and variogram analysis. Multidimensional statistical techniques are then used to select representative models of the true subsurface while exploring the uncertainty space. The resulting models will help to identify primary gaps in existing knowledge about the groundwater system and to optimize the groundwater monitoring network. A comparison with a numerical groundwater flow model will identify similarities and differences and it will be used to develop a typical hydrogeological model, which will aid the management and monitoring of the area's groundwater resources. This work will help the development of a reliable groundwater flow model to investigate future groundwater level fluctuations at the study area under climate change scenarios.</p><p> </p><p>This work was developed under the scope of the InTheMED project. InTheMED is part of the PRIMA programme supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 1923.</p>

scholarly journals The Control of Groundwater Flow Systems and Geochemical Processes on Groundwater Chemistry: A Case Study in Wushenzhao Basin, NW China

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 790 ◽  
Author(s):  
Min Lyu ◽  
Zhonghe Pang ◽  
Lihe Yin ◽  
Jun Zhang ◽  
Tianming Huang ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Flow System ◽  
Groundwater Resources ◽  
Chemical Compositions ◽  
Nw China ◽  
Water Types ◽  
Groundwater Flow Systems ◽  
Regional Flow ◽  
Flow Systems

The lowest reaches of a large-scale basin could be the discharge areas of local, intermediate and regional groundwater flow systems with significantly distinct travel distances and travel times. This study aims to delineate the groundwater chemical characteristics and the mechanism controlling the chemical evolution in the lowest reaches of the Wushenzhao Cretaceous basin, NW China. A total of 38 groundwater samples were collected and were chemically classified into five distinct water types by means of a Piper Plot. According to the hydrogeological setting and groundwater age, the spatial distribution of these water types is found to be associated with hierarchically nested groundwater flow systems (local and regional system): Types 1, 2, 3 and 4 belong to the local groundwater flow system, while type 5 belongs to the regional flow system. Graphical plots, stable isotopes and geochemical modeling techniques were used to interpret the observed compositions. The results show the dominance of carbonate and gypsum dissolution in type 1 waters; ion exchange in types 2, 3 and 4; and evaporite dissolution in type 5. In addition, human activities in the form of extensive irrigation also affect the chemical compositions of type 1 water. These findings are important for the sustainable management of groundwater resources in the study area.

scholarly journals Deep Groundwater Recharge Mechanism in the Sedimentary and Crystalline Terrains of Sri Lanka: A Study Based on Environmental Isotopic and Chemical Signatures of Spring Water

2020 ◽  
Author(s):  
Sakhila Priyadarshanee ◽  
Zhonghe Pang ◽  
Viraj Edirisinghe ◽  
H.A. Dharmagunawardhane ◽  
H.M.T.G.A. Pitawala ◽  
...  
Keyword(s):  
Sri Lanka ◽  
Geochemical Characteristics ◽  
Thermal Springs ◽  
Thermal Waters ◽  
Deep Groundwater ◽  
Flow Paths ◽  
Water Interaction ◽  
Deep Aquifers ◽  
Regional Flow ◽  
Rock Water Interaction

In many instances, dynamic, potential status and geochemical characteristics of groundwater discharging through natural springs are not well known. Present study has assessed the deep groundwater in the form of thermal and non-thermal spring in artesian condition in the selected zones in Sri Lanka, using isotope and geochemical characteristics. The results revealed that evaporation-fractional crystallization and cation-exchange in the sedimentary aquifers while rock-water interaction in crystalline deep aquifers, are the significant mechanism that control the groundwater chemistry. All the deep groundwater recharged from meteoric water at different elevations and further influenced by either evaporation or rock-water interaction during the subsurface flow. Artesian aquifers in the sedimentary terrain in the north-western coastal zones showed the recharging elevation as from 100 to 200 m amsl. They are not mixed with sea water and slightly impacted by the locally evaporated surface waters. Almost all these waters are comparatively old; indicating slow movement along the regional flow paths. Considering the recharge and discharge conditions of artesian non-thermal waters in the Southern lowlands of crystalline terrain can be classified as non-mixed, non-evaporated and young groundwater with higher elevation recharge. The artesian non-thermal waters in the East North Central lowlands, have shown the same characteristics but with evaporated conditions. All artesian thermal waters are tritium free, hence they are older and deep percolated. Intensive rock-water interaction and higher altitude origin were observed in some thermal springs. Some spring clusters in the weathered overburden have shown significant mixing with recent local rains. Non-mixed, non-evaporated and less rock-water interacted nature is a significant in two thermal springs that emerges through (chemically inert) quartzite bed rock. Both thermal and non-thermal water with artesian condition have clearly indicated that they are originated from a common recharge source but with different flow paths in different penetration depths and travel distances, resulting different chemical characteristics. Fresh water springs are mostly young and recharged from local rains followed with shallow percolation.

scholarly journals Anthropogenic disturbances of natural ecohydrological processes in the Matlabas mountain mire, South Africa

2019 ◽  
Vol 115 (5/6) ◽  
Author(s):  
Antoinette Bootsma ◽  
Samer Elshehawi ◽  
Ab Grootjans ◽  
Piet-Louis Grundling ◽  
Steven Khosa ◽  
...  
Keyword(s):  
South Africa ◽  
Groundwater Flow ◽  
Southern Africa ◽  
Wetland Management ◽  
Terrestrial Vegetation ◽  
Deep Groundwater ◽  
Near Surface ◽  
Water Flows ◽  
Access Road ◽  
Isotope Content

Matlabas is a mountain mire in Marakele National Park, located within the headwaters of the Limpopo River in South Africa. This mire consists of a complex of valley-bottom and seepage wetlands with small elevated peat domes. The occurrence of one decaying peat dome, which has burnt, and desiccated wetland areas with terrestrial vegetation has raised concerns. The aim of this study was to understand the mire features and water flows in order to identify the potential drivers causing wetland degradation. Wells and piezometers were installed to monitor the hydraulic head and collect water samples for analysis of ion composition, 18O and 2H stable isotope content, and δ13C and 14C isotope content for radiocarbon dating. Moreover, peat temperature profiles were measured and peat deposits were also dated using radiocarbon. Results indicate that the Matlabas mire developed in the lowest central-east side of the valley by paludification at the onset of the Holocene. During the Mid-Holocene, peat development was extended laterally by autogenic and allogenic processes. Three types of water flows driving peat development were identified – sheet flow, phreatic groundwater flow and deep groundwater flow – two of which are surface or near surface flows. The recent occurrence of decaying peat domes and desiccated wetland areas is possibly related to loss of exfiltrating deep groundwater flows that have resulted from drainage by the head-cut channels in the mire and interception of near surface water flow by an access road, respectively. Interventions should be undertaken to prevent further degradation of the mire. Significance: This study is the first, as far as we are aware, on the ecohydrology of an inland mountainous mire in southern Africa. The results highlight the importance of the current wetland management (including rehabilitation) initiatives in South Africa. The integrative ecohydrological methods can be applied in other headwater wetlands in southern Africa.

scholarly journals Multi-Technique groundwater flow system analysis and dating of deep aquifers in Alessandria Basin (Piedmont - IT)

2020 ◽  
Author(s):  
Nicola Quaranta ◽  
Elena Cogo ◽  
Adriano Simoni ◽  
Elisa Sacchi ◽  
Mariachiara Caschetto ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Groundwater Flow ◽  
System Analysis ◽  
Dissolved Inorganic Carbon ◽  
Flow System ◽  
Isotope Composition ◽  
Radioactive Isotopes ◽  
Deep Groundwater ◽  
Groundwater Flow System ◽  
Deep Aquifers

The aim of the study was to set up a protection system from pollution of the deep aquifer of the Alessandria basin, by redefining the recharge areas, focused on this portion of Piedmont territory, and therefore by creating some reserve areas of deep groundwater, to be preserved for future human drinking purposes. In addition to the classical hydrodynamic and geochemical monitoring techniques, the groundwaters were analyzed with reference to a monitoring network of 25 selected wells with deep screens (80-300 m below ground surface) combining radiochemical dating (14C and δ13C of dissolved inorganic carbon - DIC) with anthropogenic tracers (CFCs, SF6) as indicators of recent recharge/ mixing. Stable isotope composition (δ2H and δ18O – H2O) was assessed during a 1-year sampling of snow-rain precipitations gauges distributed in altitude in order to define Local Meteoric Water Lines; the isotopic composition was also seasonally measured for the main rivers and in selected deep-wells. The 3D numerical model was implemented in FEflow platform and calibrated on the basis of the available monitoring data; it was used as a support tool in the delimitation of the recharge areas, starting from the analysis of the distribution of flows. This model was crucial for delimiting the “reserve areas”, since it was able to simulate groundwater flows using both purely advective transport conditions (particle tracking technique), and more realistic conditions of advective and dispersive transport, by introducing dispersive parameters and using the Life Time Expectancy (LTE) reservoir distribution. The integrated use of “traditional” techniques of regional groundwater flow system monitoring (hydrochemistry, stable isotopic composition) and of dating techniques based on radioactive isotopes and anthropogenic tracers, provided a reliable support to the validation of flow and transport simulation model, oriented to identify recharge areas and “reserve areas” of future extraction of deep groundwater for drinking purpose.

scholarly journals Salinity of deep groundwater in California: Water quantity, quality, and protection

2016 ◽  
Vol 113 (28) ◽  
pp. 7768-7773 ◽  
Author(s):  
Mary Kang ◽  
Robert B. Jackson
Keyword(s):  
Oil And Gas ◽  
Saline Water ◽  
Groundwater Resources ◽  
Central Valley ◽  
Deep Groundwater ◽  
Depth Data ◽  
Deep Aquifers ◽  
California's Central Valley ◽  
Oil Gas ◽  
California’S Central Valley

Deep groundwater aquifers are poorly characterized but could yield important sources of water in California and elsewhere. Deep aquifers have been developed for oil and gas extraction, and this activity has created both valuable data and risks to groundwater quality. Assessing groundwater quantity and quality requires baseline data and a monitoring framework for evaluating impacts. We analyze 938 chemical, geological, and depth data points from 360 oil/gas fields across eight counties in California and depth data from 34,392 oil and gas wells. By expanding previous groundwater volume estimates from depths of 305 m to 3,000 m in California’s Central Valley, an important agricultural region with growing groundwater demands, fresh [<3,000 ppm total dissolved solids (TDS)] groundwater volume is almost tripled to 2,700 km3, most of it found shallower than 1,000 m. The 3,000-m depth zone also provides 3,900 km3 of fresh and saline water, not previously estimated, that can be categorized as underground sources of drinking water (USDWs; <10,000 ppm TDS). Up to 19% and 35% of oil/gas activities have occurred directly in freshwater zones and USDWs, respectively, in the eight counties. Deeper activities, such as wastewater injection, may also pose a potential threat to groundwater, especially USDWs. Our findings indicate that California’s Central Valley alone has close to three times the volume of fresh groundwater and four times the volume of USDWs than previous estimates suggest. Therefore, efforts to monitor and protect deeper, saline groundwater resources are needed in California and beyond.

scholarly journals Groundwater flow processes and mixing in active volcanic systems: the case of Guadalajara (Mexico)

2015 ◽  
Vol 12 (2) ◽  
pp. 1599-1631
Author(s):  
A. Hernández-Antonio ◽  
J. Mahlknecht ◽  
C. Tamez-Meléndez ◽  
J. Ramos-Leal ◽  
A. Ramírez-Orozco ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Agricultural Practices ◽  
Principal Component ◽  
Distribution Patterns ◽  
Groundwater Chemistry ◽  
Polluted Water ◽  
Regional Flow ◽  
Flow Processes ◽  
Production Wells ◽  
Hydrothermal Water

Abstract. Groundwater chemistry and isotopic data from 40 production wells in the Atemajac and Toluquilla Valleys, located in and around the Guadalajara metropolitan area, were determined to develop a conceptual model of groundwater flow processes and mixing. Multivariate analysis including cluster analysis and principal component analysis were used to elucidate distribution patterns of constituents and factors controlling groundwater chemistry. Based on this analysis, groundwater was classified into four groups: cold groundwater, hydrothermal water, polluted groundwater and mixed groundwater. Cold groundwater is characterized by low temperature, salinity, and Cl and Na concentrations and is predominantly of Na-HCO3 type. It originates as recharge at Primavera caldera and is found predominantly in wells in the upper Atemajac Valley. Hydrothermal water is characterized by high salinity, temperature, Cl, Na, HCO3, and the presence of minor elements such as Li, Mn and F. It is a mixed HCO3 type found in wells from Toluquilla Valley and represents regional flow circulation through basaltic and andesitic rocks. Polluted groundwater is characterized by elevated nitrate and sulfate concentrations and is usually derived from urban water cycling and subordinately from agricultural practices. Mixed groundwaters between cold and hydrothermal components are predominantly found in the lower Atemajac Valley. Tritium method elucidated that practically all of the sampled groundwater contains at least a small fraction of modern water. The multivariate mixing model M3 indicates that the proportion of hydrothermal fluids in sampled well water is between 13 (local groundwater) and 87% (hydrothermal water), and the proportion of polluted water in wells ranges from 0 to 63%. This study may help local water authorities to identify and quantify groundwater contamination and act accordingly.

scholarly journals APPLICATION OF FEFLOW FOR THE SIMULATION OF GROUNDWATER FLOW AT THE TIRNAVOS (CENTRAL GREECE) ALLUVIAL BASIN AQUIFER SYSTEM

2017 ◽  
Vol 43 (4) ◽  
pp. 1747 ◽  
Author(s):  
I. Koukidou ◽  
A. Panagopoulos
Keyword(s):  
Groundwater Flow ◽  
Groundwater Resources ◽  
Negative Effects ◽  
Simulation Code ◽  
Aquifer System ◽  
Practical Applications ◽  
Central Greece ◽  
Field Data Analysis ◽  
The Mathematical Model ◽  
First Time

FEFLOW is a relatively new simulation code that was applied and tested systematically for the first time in Greece at Tirnavos alluvial basin, which is part of the eastern Thessaly plain. The aim of this exercise is to apply and test the applicability and versatility of FEFLOW in the simulation of groundwater flow of the Tirnavos basin aquifer system, which is located in eastern Thessaly-central Greece. From the compilation and calibration of the mathematical model, it can be concluded that FEFLOW is a very powerful tool with many practical applications and capabilities. Application of FEFLOW at Tirnavos basin was successful. As deduced by field data analysis, groundwater resources of the study area are overexploited, a fact which bears negative effects not only for the study area, but also for the surrounding area, which is much greater in extent. This fact was well reproduced in the simulation. It is therefore of utmost importance to rationally manage regional groundwater resources aiming at aquifer restoration (quantity and chemical quality) and the environmental protection of both the aquifer system and the depended and interrelated ecosystems, in accordance to the water related EC Directives.

scholarly journals Solutions for groundwater flow with sloping stream boundary: analytical, numerical and experimental models

2017 ◽  
Vol 49 (4) ◽  
pp. 1120-1130 ◽  
Author(s):  
Uğur Boyraz ◽  
Cevza Melek Kazezyılmaz-Alhan
Keyword(s):  
Surface Water ◽  
Groundwater Flow ◽  
Laboratory Experiments ◽  
Groundwater Resources ◽  
Experimental Models ◽  
Flow Equation ◽  
Visual Modflow ◽  
Aquifer System ◽  
Aquifer Characteristics ◽  
Made In

Abstract Protecting groundwater resources plays an important role in watershed management. For this purpose, studies on groundwater flow dynamics incorporating surface water–groundwater interactions have been conducted including analytical, numerical, and experimental models. In this research, a stream–aquifer system was considered to understand the physical behavior of surface water–groundwater interactions. Interactions in a stream–aquifer system were incorporated into the mathematical modeling by defining the stream head as a boundary condition for the groundwater flow equation. This boundary was chosen as a sloping stream boundary, which is an approach in representing the natural conditions of the stream and may be used to define continuous interactions between stream and aquifer. A semi-analytical solution for transient 2D groundwater flow was developed for the considered problem. Isotropic, homogeneous, and finite aquifer assumptions were made in order to define the aquifer characteristics. Then, a series of laboratory experiments was conducted to simulate this stream–aquifer system. Finally, a numerical model was developed by using Visual MODFLOW to verify analytical and experimental results. Numerical results matched with both analytical solutions and the experimental observations.

scholarly journals Geological and hydrogeological assessment of the Brito Formation: Municipio de Tola, Nicaragua

2021 ◽  
Author(s):  
James K. Adamson ◽  
G. Thomas LaVanchy ◽  
Brandon Stone ◽  
James A. Clark ◽  
Stuart J. Dykstra ◽  
...  
Keyword(s):  
Climate Change ◽  
Groundwater Recharge ◽  
Groundwater Resources ◽  
Flow Characteristics ◽  
Primary Source ◽  
Secondary Porosity ◽  
Aquifer System ◽  
Aquifer Storage ◽  
Groundwater Availability ◽  
Regional Flow

AbstractThere are sparse hydrogeological data and insufficient hydrogeological knowledge in many areas of the world reliant on groundwater. Nicaragua’s Pacific coast is one such region that is also experiencing water scarcity resulting from increasing demand on groundwater resources and climate change. The primary source of water in the region is the aquifer system associated with the Brito Formation, which is a marine sedimentary stratum of mostly sandstone that blankets 75 km of coastline in southwest Nicaragua. This study focused on the Tola municipality with the objective to advance a conceptual understanding of the hydrogeology and to support sustainable water development. Results demonstrate a heterogeneous aquifer system with regional flow characteristics and other factors that influence groundwater availability and water quality. Primary porosity is low, and secondary porosity is the primary mechanism of aquifer storage and is influenced by geological structure and diagenesis processes. Groundwater recharge is spatially and temporally heterogeneous and direct recharge is low. Infiltration of streamflow and runoff, especially early in the rainy season, is thought to be a large component of groundwater recharge. Climate, flow and recharge dynamics, and low storage capacity make the Brito Formation a sensitive resource and vulnerable to drought, increased abstraction, and climate change. This assessment provides data and insights useful for informing future studies and investments within the region and may be applicable in other Central American and Caribbean nations with coastal sandstone aquifers.

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