scholarly journals Regional groundwater flow and karst evolution–theoretical approach and example from Switzerland

2021 ◽  
Vol 80 (5) ◽  
Author(s):  
Stefan Scheidler ◽  
Peter Huggenberger ◽  
Horst Dresmann ◽  
Adrian Auckenthaler ◽  
Jannis Epting
Keyword(s):  
Groundwater Flow ◽  
Groundwater Recharge ◽  
Regional Scale ◽  
Karst Aquifer ◽  
River Rhine ◽  
Aquifer Systems ◽  
Groundwater Circulation ◽  
Lithostratigraphic Units ◽  
Upper Muschelkalk ◽  
Recharge Rates

AbstractIn regional scale aquifers in the Rhine Valley and Tabular Jura east of Basel (Switzerland), the groundwater circulation was investigated using regional-scale geological and hydraulic 3D models. The main aquifers in the area comprise the Quaternary aquifer of unconsolidated gravel deposits along the River Rhine and its tributaries, as well as the regional scale karst aquifer within the Upper Muschelkalk. Land subsidence, a process likely associated with salt solution mining, indicates further subordinate groundwater bearing segments and complex groundwater interactions along fault zones. In the aquifer systems we investigated, regional-scale groundwater circulation was simulated and visualized in relation to the geological settings. Lithostratigraphic units and fault structures were parameterized and analyzed, including the sensitivity of hydraulic properties and boundaries. Scenario calculations were used to investigate the sensitivity that the aquifer systems had to hydraulic parameter changes during Quaternary aggradation and degradation in the main valley. Those calculations were also done for base-level changes in the Rivers Rhine and Birs. For this purpose, this study considered probable historic base-levels before river regulation occurred, and before river dams and power plants were constructed. We also focused on scenarios considering increased groundwater recharge rates, e.g. due to exceptional long-lasting precipitation, or heavy rainfall events in the catchment area. Our results indicate that increased groundwater recharge rates in the catchment areas during such events (or periods) are associated with orders of magnitude increases of regional inflow into the Upper Muschelkalk karst aquifer. Furthermore, the groundwater fluctuations and groundwater saturated regions within the karst aquifer shift to places where high densities of sinkholes are documented. When the surface water base-levels adapt to probable historic levels, it leads to increased hydraulic gradients (i.e. local lowering of the groundwater level by up to 7 m). Those increased gradients are associated with increased groundwater flow within some aquifer regions that are particularly prone to karst development.

scholarly journals A high resolution global scale groundwater model

2014 ◽  
Vol 11 (5) ◽  
pp. 5217-5250 ◽  
Author(s):  
I. E. M. de Graaf ◽  
E. H. Sutanudjaja ◽  
L. P. H. van Beek ◽  
M. F. P. Bierkens
Keyword(s):  
Groundwater Flow ◽  
Land Surface ◽  
Regional Scale ◽  
Land Surface Model ◽  
Global Scale ◽  
Water Levels ◽  
Natural State ◽  
Surface Model ◽  
Groundwater Model ◽  
Aquifer Systems

Abstract. Groundwater is the world's largest accessible source of fresh water. It plays a vital role in satisfying needs for drinking water, agriculture and industrial activities. During times of drought groundwater sustains baseflow to rivers and wetlands, thereby supporting ecosystems. Most global scale hydrological models (GHMs) do not include a groundwater flow component, mainly due to lack of geohydrological data at the global scale. For the simulation of lateral flow and groundwater head dynamics a realistic physical representation of the groundwater system is needed, especially for GHMs that run at finer resolution. In this study we present a global scale groundwater model (run at 6' as dynamic steady state) using MODFLOW to construct an equilibrium water table at its natural state as the result of long-term climatic forcing. The aquifer schematization and properties were based on available global datasets of lithology and transmissivities combined with estimated aquifer thickness of an upper unconfined aquifer. The model is forced with outputs from the land-surface model PCR-GLOBWB, specifically with net recharge and surface water levels. A sensitivity analysis, in which the model was run with various parameter settings, showed variation in saturated conductivity causes most of the groundwater level variations. Simulated groundwater heads were validated against reported piezometer observations. The validation showed that groundwater depths are reasonably well simulated for many regions of the world, especially for sediment basins (R2 = 0.95). The simulated regional scale groundwater patterns and flowpaths confirm the relevance of taking lateral groundwater flow into account in GHMs. Flowpaths show inter-basin groundwater flow that can be a significant part of a basins water budget and helps to sustain river baseflow, explicitly during times of droughts. Also important aquifer systems are recharged by inter-basin groundwater flows that positively affect water availability.

scholarly journals A high-resolution global-scale groundwater model

2015 ◽  
Vol 19 (2) ◽  
pp. 823-837 ◽  
Author(s):  
I. E. M. de Graaf ◽  
E. H. Sutanudjaja ◽  
L. P. H. van Beek ◽  
M. F. P. Bierkens
Keyword(s):  
Groundwater Flow ◽  
Land Surface ◽  
Regional Scale ◽  
Unconfined Aquifer ◽  
Global Scale ◽  
Water Levels ◽  
Natural State ◽  
Groundwater Model ◽  
Groundwater Levels ◽  
Aquifer Systems

Abstract. Groundwater is the world's largest accessible source of fresh water. It plays a vital role in satisfying basic needs for drinking water, agriculture and industrial activities. During times of drought groundwater sustains baseflow to rivers and wetlands, thereby supporting ecosystems. Most global-scale hydrological models (GHMs) do not include a groundwater flow component, mainly due to lack of geohydrological data at the global scale. For the simulation of lateral flow and groundwater head dynamics, a realistic physical representation of the groundwater system is needed, especially for GHMs that run at finer resolutions. In this study we present a global-scale groundwater model (run at 6' resolution) using MODFLOW to construct an equilibrium water table at its natural state as the result of long-term climatic forcing. The used aquifer schematization and properties are based on available global data sets of lithology and transmissivities combined with the estimated thickness of an upper, unconfined aquifer. This model is forced with outputs from the land-surface PCRaster Global Water Balance (PCR-GLOBWB) model, specifically net recharge and surface water levels. A sensitivity analysis, in which the model was run with various parameter settings, showed that variation in saturated conductivity has the largest impact on the groundwater levels simulated. Validation with observed groundwater heads showed that groundwater heads are reasonably well simulated for many regions of the world, especially for sediment basins (R2 = 0.95). The simulated regional-scale groundwater patterns and flow paths demonstrate the relevance of lateral groundwater flow in GHMs. Inter-basin groundwater flows can be a significant part of a basin's water budget and help to sustain river baseflows, especially during droughts. Also, water availability of larger aquifer systems can be positively affected by additional recharge from inter-basin groundwater flows.

scholarly journals Estimating annual groundwater recharge coefficient for karst aquifers of the southern Apennines (Italy)

2014 ◽  
Vol 18 (2) ◽  
pp. 803-817 ◽  
Author(s):  
V. Allocca ◽  
F. Manna ◽  
P. De Vita
Keyword(s):  
Land Use ◽  
Time Series ◽  
Groundwater Recharge ◽  
Regional Scale ◽  
Karst Aquifer ◽  
Spring Discharge ◽  
Karst Aquifers ◽  
Southern Apennines ◽  
The Mean ◽  
Groundwater Outflow

Abstract. To assess the mean annual groundwater recharge of the karst aquifers in the southern Apennines (Italy), the estimation of the mean annual groundwater recharge coefficient (AGRC) was conducted by means of an integrated approach based on hydrogeological, hydrological, geomorphological, land use and soil cover analyses. Starting from the hydrological budget equation, the coefficient was conceived as the ratio between the net groundwater outflow and the precipitation minus actual evapotranspiration (P − ETR) for a karst aquifer. A large part of the southern Apennines, which is covered by a meteorological network containing 40 principal karst aquifers, was studied. Using precipitation and air temperature time series gathered through monitoring stations operating in the period 1926–2012, the mean annual P − ETR was estimated, and its distribution was modelled at a regional scale by considering the orographic barrier and rain shadow effects of the Apennine chain, as well as the altitudinal control. Four sample karst aquifers with available long spring discharge time series were identified for estimating the AGRC. The resulting values were correlated with other parameters that control groundwater recharge, such as the extension of outcropping karst rocks, morphological settings, land use and covering soil type. A multiple linear regression between the AGRC, lithology and the summit plateau and endorheic areas was found. This empirical model was used to assess the AGRC and mean annual groundwater recharge in other regional karst aquifers. The coefficient was calculated as ranging between 50 and 79%, thus being comparable with other similar estimations carried out for karst aquifers of European and Mediterranean countries. The mean annual groundwater recharge for karst aquifers of the southern Apennines was assessed by these characterizations and validated by a comparison with available groundwater outflow measurements. These results represent a deeper understanding of an aspect of groundwater hydrology in karst aquifers which is fundamental for the formulation of appropriate management models of groundwater resources at a regional scale, also taking into account mitigation strategies for climate change impacts. Finally, the proposed hydrological characterizations are also supposed to be useful for the assessment of mean annual runoff over carbonate mountains, which is another important topic concerning water management in the southern Apennines.

scholarly journals Numerical modeling of the groundwater flow in the fractured and karst aquifer of the Salento peninsula (Southern Italy)

2013 ◽  
Author(s):  
Giovanna De Filippis ◽  
Mauro Giudici ◽  
Stefano Margiotta ◽  
Fiorella Mazzone ◽  
Sergio Negrini ◽  
...  
Keyword(s):  
Water Balance ◽  
Groundwater Flow ◽  
Conceptual Model ◽  
Southern Italy ◽  
Climatic Factors ◽  
Groundwater Resources ◽  
Regional Scale ◽  
Karst Aquifer ◽  
Aquifer System ◽  
Complex Relationships

Water resources represented by coastal aquifers are very important for regions characterized by a relevant request of freshwater, but limited rainfall, lack of surface water bodies and intrusion of the seawater through the sediments which host groundwater. Therefore some coastal areas, like the Salento peninsula (southern Italy), are subjected to the risk of desertification and a proper management of groundwater resources requires tools to analyze and predict the water balance and the evolution of the physical system in response to human activities (e.g., ground water withdrawals) and climatic factors. The Salento peninsula is a typical Mediterranean basin, where the main water resource is the aquifer hosted in Cretaceous carbonatic rocks (Calcare di Altamura, Altamura limestone): this is a fractured and karst aquifer, with a poor recharge and complex relationships with the sea. In order to develop a tool to assess the water balance at regional scale for the considered aquifer system, a groundwater flow model was developed by Giudici et al. (2012a); it is based on a conceptual model obtained from a reconstruction of the hydrostratigraphic architecture of the region, which includes the main aquifer and the overlaying rocks characterized by low permeability which can host local and relatively thin aquifers. In this paper that work is updated, by improving the reconstruction of the hydraulic head and of the conceptual model, above all in those areas that the previous model evidenced as critical for the absence of fresh water along the whole aquifer thickness. Moreover, since the estimate of some model’s input parameters is affected by high uncertainty, a sensitivity analysis is performed to evaluate the effects of this uncertainty on the model’s results.

scholarly journals Regional Groundwater Modeling of the Guarani Aquifer System

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2323 ◽  
Author(s):  
Roger D. Gonçalves ◽  
Elias H. Teramoto ◽  
Hung K. Chang
Keyword(s):  
Water Balance ◽  
Groundwater Flow ◽  
Groundwater Recharge ◽  
Flow Model ◽  
Minor Amount ◽  
Groundwater Flow Model ◽  
Aquifer System ◽  
Gas System ◽  
Guarani Aquifer ◽  
Recharge Rates

The Guarani Aquifer System (GAS) is a strategic transboundary aquifer system shared by Brazil, Argentina, Paraguay and Uruguay. This article presents a groundwater flow model to assess the GAS system in terms of regional flow patterns, water balance and overall recharge. Despite the continental dimension of GAS, groundwater recharge is restricted to narrow outcrop zones. An important part is discharged into local watersheds, whereas a minor amount reaches the confined part. A three-dimensional finite element groundwater-flow model of the entire GAS system was constructed to obtain a better understanding of the prevailing flow dynamics and more reliable estimates of groundwater recharge. Our results show that recharge rates effectively contributing to the regional GAS water balance are only approximately 0.6 km3/year (about 4.9 mm/year). These rates are much smaller than previous estimates, including of deep recharge approximations commonly used for water resources management. Higher recharge rates were also not compatible with known 81Kr groundwater age estimates, as well as with calculated residence times using a particle tracking algorithm.

scholarly journals Imbalance in the modern hydrologic budget of topographic catchments along the western slope of the Andes (21–25 S)

2018 ◽  
Author(s):  
David Boutt ◽  
Lilly Corenthal ◽  
Lee Ann Munk ◽  
Scott Hynek
Keyword(s):  
Groundwater Flow ◽  
Water Table ◽  
Water Discharge ◽  
Regional Scale ◽  
Western Slope ◽  
The Andes ◽  
Regional Flow ◽  
Lower Elevation ◽  
Hydrologic Budget ◽  
Recharge Rates

Rates of water discharge often exceed groundwater recharge in arid catchments. This apparent mass imbalance within a catchment may be reconciled through either regional-scale groundwater flow between topographic drainages and/or the draining of stored groundwater recharged during pluvial periods. We investigate discrepancies in the modern hydrologic budget of catchments along the west flank of the Andes in northern Chile (21–25° S), focused on the endorheic Salar de Atacama basin, and adjacent basins. Our new, uncertainty bounded, estimates of modern recharge rates do not come close to balancing observed modern groundwater discharge within topographic catchments. Two geologically realistic conceptualizations of hydrogeologic catchments discharging to Salar de Atacama were explored with a 2D groundwater model. Results from models support the interpretation that both regional flow and transient drainage of groundwater from storage are required to balance water budgets along the plateau margin. The models further examine whether this system is still responding to climatic forcing from pluvial periods and highlight general characteristics for similar plateau margin systems including: (1) water level changes at the plateau margin are highly sensitive to changes in recharge on the plateau, (2) extent and magnitude of the changes in water table are controlled by the distribution of hydraulic conductivity at the margin, (3) contributing area to the lower elevation catchment is itself dynamic, and not coincident with the topographic boundary, and (4) difficulty in reconciling the modern position of “the water table” on the Andean plateau with the regional groundwater flow conceptualization and modern discharge to low lying catchments.

scholarly journals An Assessment of Groundwater Recharge at A Regional Scale for Sustainable Resource Management: Province of Alicante (SE Spain)

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 862
Author(s):  
Miguel Fernández-Mejuto ◽  
José Miguel Andreu ◽  
Ernesto García-Sánchez ◽  
Rebeca Palencia
Keyword(s):  
Regional Scale ◽  
Climatic Conditions ◽  
Groundwater Exploitation ◽  
Flow Models ◽  
Sustainable Resource Management ◽  
Aquifer Systems ◽  
Spring Flow ◽  
Recharge Rates ◽  
Insufficient Knowledge ◽  
Regional Water

For decades, the Province of Alicante, located in the Southeast of Spain, has experienced important economic development associated with groundwater exploitation. The scarcity of superficial resources and irregular distribution in the time and space of rainfall, typical of the Mediterranean environment, together with the extensive limestone outcrops, have made groundwater a key resource for the area. However, insufficient knowledge about aquifers, especially the lack of precise recharge estimates, hinders regional water management. This study establishes updated recharge estimates and water budgets for the 200 aquifers found in Alicante, using readily usable methodologies and available data. These are soil water budget models, groundwater flow models, water table fluctuation methods, and spring flow analyses. The results show low mean annual values of recharge from precipitation (69 mm/year and a coefficient of 12%) and two main differentiated domains. The first one, in the northeast of the province, under more humid climatic conditions with larger carbonate aquifer systems, has higher recharge coefficients, ranging from 14% to 24%, and greater resources. For the rest of the province, where aquifers are smaller and annual averages of rainfall range between 250 and 400 mm, average recharge rates are low (9–12%).

scholarly journals Common problematic aspects of coupling hydrological models with groundwater flow models on the river catchment scale

2006 ◽  
Vol 9 ◽  
pp. 63-71 ◽  
Author(s):  
R. Barthel
Keyword(s):  
Groundwater Flow ◽  
Groundwater Recharge ◽  
Large Scale ◽  
Regional Scale ◽  
Integrated Water Resources Management ◽  
Model Coupling ◽  
Hydrological Models ◽  
Catchment Scale ◽  
Common Definition ◽  
Definition Of

Abstract. Model coupling requires a thorough conceptualisation of the coupling strategy, including an exact definition of the individual model domains, the "transboundary" processes and the exchange parameters. It is shown here that in the case of coupling groundwater flow and hydrological models – in particular on the regional scale – it is very important to find a common definition and scale-appropriate process description of groundwater recharge and baseflow (or "groundwater runoff/discharge") in order to achieve a meaningful representation of the processes that link the unsaturated and saturated zones and the river network. As such, integration by means of coupling established disciplinary models is problematic given that in such models, processes are defined from a purpose-oriented, disciplinary perspective and are therefore not necessarily consistent with definitions of the same process in the model concepts of other disciplines. This article contains a general introduction to the requirements and challenges of model coupling in Integrated Water Resources Management including a definition of the most relevant technical terms, a short description of the commonly used approach of model coupling and finally a detailed consideration of the role of groundwater recharge and baseflow in coupling groundwater models with hydrological models. The conclusions summarize the most relevant problems rather than giving practical solutions. This paper aims to point out that working on a large scale in an integrated context requires rethinking traditional disciplinary workflows and encouraging communication between the different disciplines involved. It is worth noting that the aspects discussed here are mainly viewed from a groundwater perspective, which reflects the author's background.

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